Issue #1829 - Revert "Issue #1751 - Remove MacOS support from configure"

This reverts commit d3543ca2fecf39a83952872c0b936e4566fe02ff.

9 files changed, 1749 insertions, 0 deletions

diff --git a/build/macosx/build-cctools.sh b/build/macosx/build-cctools.sh
new file mode 100755
index 0000000000..af0b36221b
--- /dev/null
+++ b/build/macosx/build-cctools.sh
@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -e
+
+if ! git remote -v | grep origin | grep -q cctools-port; then
+    echo "must be in a cctools-port checkout"
+    exit 1
+fi
+
+mkdir build-cctools
+cd build-cctools
+
+CFLAGS='-mcpu=generic -mtune=generic' MACOSX_DEPLOYMENT_TARGET=10.7 ../cctools/configure --target=x86_64-apple-darwin11
+env MACOSX_DEPLOYMENT_TARGET=10.7 make -s -j4
+
+if test ! -e ld64/src/ld/ld; then
+    echo "ld did not get built"
+    exit 1
+fi
+
+gtar jcf cctools.tar.bz2 ld64/src/ld/ld --transform 's#ld64/src/ld#cctools/bin#'
+
+cd ../
+
+echo "build from $(git show --pretty=format:%H -s HEAD) complete!"
+echo "upload the build-cctools/cctools.tar.bz2 file to tooltool"
diff --git a/build/macosx/cross-mozconfig.common b/build/macosx/cross-mozconfig.common
new file mode 100644
index 0000000000..8e56394d00
--- /dev/null
+++ b/build/macosx/cross-mozconfig.common
@@ -0,0 +1,47 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+MOZ_AUTOMATION_L10N_CHECK=0
+
+if [ "x$IS_NIGHTLY" = "xyes" ]; then
+  # Some nightlies (eg: Mulet) don't want these set.
+  MOZ_AUTOMATION_UPDATE_PACKAGING=${MOZ_AUTOMATION_UPDATE_PACKAGING-1}
+  MOZ_AUTOMATION_SDK=${MOZ_AUTOMATION_SDK-1}
+fi
+. "$topsrcdir/build/mozconfig.common"
+
+# ld needs libLTO.so from llvm
+mk_add_options "export LD_LIBRARY_PATH=$topsrcdir/clang/lib"
+
+CROSS_CCTOOLS_PATH=$topsrcdir/cctools
+CROSS_SYSROOT=$topsrcdir/MacOSX10.7.sdk
+CROSS_PRIVATE_FRAMEWORKS=$CROSS_SYSROOT/System/Library/PrivateFrameworks
+FLAGS="-target x86_64-apple-darwin10 -mlinker-version=136 -B $CROSS_CCTOOLS_PATH/bin -isysroot $CROSS_SYSROOT"
+
+export CC="$topsrcdir/clang/bin/clang $FLAGS"
+export CXX="$topsrcdir/clang/bin/clang++ $FLAGS"
+export CPP="$topsrcdir/clang/bin/clang $FLAGS -E"
+export LLVMCONFIG=$topsrcdir/clang/bin/llvm-config
+export LDFLAGS="-Wl,-syslibroot,$CROSS_SYSROOT -Wl,-dead_strip"
+export TOOLCHAIN_PREFIX=$CROSS_CCTOOLS_PATH/bin/x86_64-apple-darwin10-
+export DSYMUTIL=$topsrcdir/clang/bin/llvm-dsymutil
+export GENISOIMAGE=$topsrcdir/genisoimage/genisoimage
+export DMG_TOOL=$topsrcdir/dmg/dmg
+
+export HOST_CC="$topsrcdir/clang/bin/clang"
+export HOST_CXX="$topsrcdir/clang/bin/clang++"
+export HOST_CPP="$topsrcdir/clang/bin/clang -E"
+export HOST_CFLAGS="-g"
+export HOST_CXXFLAGS="-g"
+export HOST_LDFLAGS="-g"
+
+ac_add_options --target=x86_64-apple-darwin
+ac_add_options --with-macos-private-frameworks=$CROSS_PRIVATE_FRAMEWORKS
+
+# Enable static analysis checks by default on OSX cross builds.
+ac_add_options --enable-clang-plugin
+
+. "$topsrcdir/build/mozconfig.cache"
+
+export SOCORRO_SYMBOL_UPLOAD_TOKEN_FILE=/builds/crash-stats-api.token
diff --git a/build/macosx/local-mozconfig.common b/build/macosx/local-mozconfig.common
new file mode 100644
index 0000000000..02a09d2fe0
--- /dev/null
+++ b/build/macosx/local-mozconfig.common
@@ -0,0 +1,46 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+if [ "x$IS_NIGHTLY" = "xyes" ]; then
+  # Some nightlies (eg: Mulet) don't want these set.
+  MOZ_AUTOMATION_UPLOAD_SYMBOLS=${MOZ_AUTOMATION_UPLOAD_SYMBOLS-1}
+  MOZ_AUTOMATION_UPDATE_PACKAGING=${MOZ_AUTOMATION_UPDATE_PACKAGING-1}
+  MOZ_AUTOMATION_SDK=${MOZ_AUTOMATION_SDK-1}
+fi
+. "$topsrcdir/build/mozconfig.common"
+
+if [ -d "$topsrcdir/clang" ]; then
+    # mozilla-central based build
+    export CC=$topsrcdir/clang/bin/clang
+    export CXX=$topsrcdir/clang/bin/clang++
+    export LLVMCONFIG=$topsrcdir/clang/bin/llvm-config
+    export DSYMUTIL=$topsrcdir/clang/bin/llvm-dsymutil
+    # Use an updated linker.
+    ldflags="-B$topsrcdir/cctools/bin"
+elif [ -d "$topsrcdir/../clang" ]; then
+    # comm-central based build
+    export CC=$topsrcdir/../clang/bin/clang
+    export CXX=$topsrcdir/../clang/bin/clang++
+    export LLVMCONFIG=$topsrcdir/../clang/bin/llvm-config
+    export DSYMUTIL=$topsrcdir/../clang/bin/llvm-dsymutil
+    # Use an updated linker.
+    ldflags="-B$topsrcdir/../cctools/bin"
+fi
+
+# Ensure the updated linker doesn't generate things our older build tools
+# don't understand.
+ldflags="$ldflags -Wl,-no_data_in_code_info"
+export LDFLAGS="$ldflags"
+
+# If not set use the system default clang
+if [ -z "$CC" ]; then
+    export CC=clang
+fi
+
+# If not set use the system default clang++
+if [ -z "$CXX" ]; then
+    export CXX=clang++
+fi
+
+export SOCORRO_SYMBOL_UPLOAD_TOKEN_FILE=/builds/crash-stats-api.token
diff --git a/build/macosx/mozconfig.common b/build/macosx/mozconfig.common
new file mode 100644
index 0000000000..27634b7f31
--- /dev/null
+++ b/build/macosx/mozconfig.common
@@ -0,0 +1,5 @@
+if test `uname -s` = Linux; then
+  . $topsrcdir/build/macosx/cross-mozconfig.common
+else
+  . $topsrcdir/build/macosx/local-mozconfig.common
+fi
diff --git a/build/macosx/permissions/chown_revert.c b/build/macosx/permissions/chown_revert.c
new file mode 100644
index 0000000000..2cf3e37c3f
--- /dev/null
+++ b/build/macosx/permissions/chown_revert.c
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <unistd.h>
+#include <stdio.h>
+
+int main(int argc, char **argv)
+{
+  if (argc != 2)
+    return 1;
+
+  uid_t realuser = getuid();
+  char uidstring[20];
+  snprintf(uidstring, 19, "%i", realuser);
+  uidstring[19] = '\0';
+
+  return execl("/usr/sbin/chown",
+               "/usr/sbin/chown", "-R", "-h", uidstring, argv[1], (char*) 0);
+}
diff --git a/build/macosx/permissions/chown_root.c b/build/macosx/permissions/chown_root.c
new file mode 100644
index 0000000000..c9b13a5308
--- /dev/null
+++ b/build/macosx/permissions/chown_root.c
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <unistd.h>
+
+int main(int argc, char **argv)
+{
+  if (argc != 2)
+    return 1;
+
+  return execl("/usr/sbin/chown",
+               "/usr/sbin/chown", "-R", "-h", "root:admin", argv[1], (char*) 0);
+}
diff --git a/build/macosx/universal/mozconfig b/build/macosx/universal/mozconfig
new file mode 100644
index 0000000000..32ab66f2df
--- /dev/null
+++ b/build/macosx/universal/mozconfig
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# i386/x86-64 Universal Build mozconfig
+
+# As used here, arguments in $MOZ_BUILD_PROJECTS are suitable as arguments
+# to gcc's -arch parameter.
+mk_add_options MOZ_BUILD_PROJECTS="x86_64 i386"
+
+. $topsrcdir/build/macosx/universal/mozconfig.common
diff --git a/build/macosx/universal/mozconfig.common b/build/macosx/universal/mozconfig.common
new file mode 100644
index 0000000000..bb54bc6c43
--- /dev/null
+++ b/build/macosx/universal/mozconfig.common
@@ -0,0 +1,55 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+mk_add_options MOZ_UNIFY_BDATE=1
+
+DARWIN_VERSION=10
+ac_add_app_options i386 --target=i386-apple-darwin$DARWIN_VERSION
+ac_add_app_options x86_64 --target=x86_64-apple-darwin$DARWIN_VERSION
+ac_add_app_options i386 --with-unify-dist=../x86_64/dist
+ac_add_app_options x86_64 --with-unify-dist=../i386/dist
+
+if ! test `uname -s` = Linux; then
+  # Cross-universal builds already do the equivalent of this by setting -isysroot directly
+  ac_add_options --with-macos-sdk=/Developer/SDKs/MacOSX10.7.sdk
+fi
+
+. $topsrcdir/build/macosx/mozconfig.common
+
+# $MOZ_BUILD_APP is only defined when sourced by configure.  That's not a
+# problem, because the variables it affects only need to be set for
+# configure.
+if test -n "$MOZ_BUILD_APP" ; then
+if test "$MOZ_BUILD_APP" = "i386" -o "$MOZ_BUILD_APP" = "x86_64"; then
+  TARGET_CPU=$MOZ_BUILD_APP
+
+  # $HOST_CXX is presently unused.  $HOST_CC will only be used during a cross
+  # compile.
+  HOST_CC=$CC
+  HOST_CXX=$CXX
+
+  NATIVE_CPU=`$topsrcdir/build/autoconf/config.guess | cut -f1 -d-`
+
+  # It's not strictly necessary to specify -arch during native builds, but it
+  # makes the merged about:buildconfig easier to follow, and it reduces
+  # conditionalized differences between builds.
+  CC="$CC -arch $TARGET_CPU"
+  CXX="$CXX -arch $TARGET_CPU"
+
+  # These must be set for cross builds, and don't hurt straight builds.
+  RANLIB="${TOOLCHAIN_PREFIX}ranlib"
+  AR="${TOOLCHAIN_PREFIX}ar"
+  AS=$CC
+  LD=ld
+  STRIP="${TOOLCHAIN_PREFIX}strip"
+  OTOOL="${TOOLCHAIN_PREFIX}otool"
+
+  # Each per-CPU build should be entirely oblivious to the fact that a
+  # universal binary will be produced.  The exception is packager.mk, which
+  # needs to know to look for universal bits when building the .dmg.
+  UNIVERSAL_BINARY=1
+
+  export CC CXX HOST_CC HOST_CXX RANLIB AR AS LD STRIP OTOOL
+fi
+fi
diff --git a/build/macosx/universal/unify b/build/macosx/universal/unify
new file mode 100755
index 0000000000..38dd354145
--- /dev/null
+++ b/build/macosx/universal/unify
@@ -0,0 +1,1525 @@
+#!/usr/bin/perl
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+use strict;
+use warnings;
+
+=pod
+
+=head1 NAME
+
+B<unify> - Mac OS X universal binary packager
+
+=head1 SYNOPSIS
+
+B<unify>
+I<ppc-path>
+I<x86-path>
+I<universal-path>
+[B<--dry-run>]
+[B<--only-one> I<action>]
+[B<--verbosity> I<level>]
+[B<--unify-with-sort> I<regex>]
+
+=head1 DESCRIPTION
+
+I<unify> merges any two architecture-specific files or directory trees
+into a single file or tree suitable for use on either architecture as a
+"fat" or "universal binary."
+
+Architecture-specific Mach-O files will be merged into fat Mach-O files
+using L<lipo(1)>.  Non-Mach-O files in the architecture-specific trees
+are compared to ensure that they are equivalent before copying.  Symbolic
+links are permitted in the architecture-specific trees and will cause
+identical links to be created in the merged tree, provided that the source
+links have identical targets.  Directories are processed recursively.
+
+If the architecture-specific source trees contain zip archives (including
+jar files) that are not identical according to a byte-for-byte check, they
+are still assumed to be equivalent if both archives contain exactly the
+same members with identical checksums and sizes.
+
+Behavior when one architecture-specific tree contains files that the other
+does not is controlled by the B<--only-one> option.
+
+If Mach-O files cannot be merged using L<lipo(1)>, zip archives are not
+equivalent, regular files are not identical, or any other error occurs,
+B<unify> will fail with an exit status of 1.  Diagnostic messages are
+typically printed to stderr; this behavior can be controlled with the
+B<--verbosity> option.
+
+=head1 OPTIONS
+
+=over 5
+
+=item I<ppc-path>
+
+=item I<x86-path>
+
+The paths to directory trees containing PowerPC and x86 builds,
+respectively.  I<ppc-path> and I<x86-path> are permitted to contain files
+that are already "fat," and only the appropriate architecture's images will
+be used.
+
+I<ppc-path> and I<x86-path> are also permitted to both be files, in which
+case B<unify> operates solely on those files, and produces an appropriate
+merged file at I<target-path>.
+
+=item I<target-path>
+
+The path to the merged file or directory tree.  This path will be created,
+and it must not exist prior to running B<unify>.
+
+=item B<--dry-run>
+
+When specified, the commands that would be executed are printed, without
+actually executing them.  Note that B<--dry-run> and the equivalent
+B<--verbosity> level during "wet" runs may print equivalent commands when
+no commands are in fact executed: certain operations are handled internally
+within B<unify>, and an approximation of a command that performs a similar
+task is printed.
+
+=item B<--only-one> I<action>
+
+Controls handling of files that are only present in one of the two source
+trees.  I<action> may be:
+  skip - These files are skipped.
+  copy - These files are copied from the tree in which they exist.
+  fail - When this condition occurs, it is treated as an error.
+
+The default I<action> is copy.
+
+=item B<--verbosity> I<level>
+
+Adjusts the level of loudness of B<unify>.  The possible values for
+I<level> are:
+  0 - B<unify> never prints anything.
+      (Other programs that B<unify> calls may still print messages.)
+  1 - Fatal error messages are printed to stderr.
+  2 - Nonfatal warnings are printed to stderr.
+  3 - Commands are printed to stdout as they are executed.
+
+The default I<level> is 2.
+
+=item B<--unify-with-sort> I<regex>
+
+Allows merging files matching I<regex> that differ only by the ordering
+of the lines contained within them. The unified file will have its contents
+sorted. This option may be given multiple times to specify multiple
+regexes for matching files.
+
+=back
+
+=head1 EXAMPLES
+
+=over 5
+
+=item Create a universal .app bundle from two architecture-specific .app
+bundles:
+
+unify --only-one copy ppc/dist/firefox/Firefox.app
+  x86/dist/firefox/Firefox.app universal/Firefox.app
+  --verbosity 3
+
+=item Merge two identical architecture-specific trees:
+
+unify --only-one fail /usr/local /nfs/x86/usr/local
+  /tmp/usrlocal.fat
+
+=back
+
+=head1 REQUIREMENTS
+
+The only esoteric requirement of B<unify> is that the L<lipo(1)> command
+be available.  It is present on Mac OS X systems at least as early as
+10.3.9, and probably earlier.  Mac OS X 10.4 ("Tiger") or later are
+recommended.
+
+=head1 LICENSE
+
+MPL 2.
+
+=head1 AUTHOR
+
+The software was initially written by Mark Mentovai; copyright 2006
+Google Inc.
+
+=head1 SEE ALSO
+
+L<cmp(1)>, L<ditto(1)>, L<lipo(1)>
+
+=cut
+
+use Archive::Zip(':ERROR_CODES');
+use Errno;
+use Fcntl;
+use File::Compare;
+use File::Copy;
+use Getopt::Long;
+
+my (%gConfig, $gDryRun, $gOnlyOne, $gVerbosity, @gSortMatches);
+
+sub argumentEscape(@);
+sub command(@);
+sub compareZipArchives($$);
+sub complain($$@);
+sub copyIfIdentical($$$);
+sub slurp($);
+sub get_sorted($);
+sub compare_sorted($$);
+sub copyIfIdenticalWhenSorted($$$);
+sub createUniqueFile($$);
+sub makeUniversal($$$);
+sub makeUniversalDirectory($$$);
+sub makeUniversalInternal($$$$);
+sub makeUniversalFile($$$);
+sub usage();
+sub readZipCRCs($);
+
+{
+  package FileAttrCache;
+
+  sub new($$);
+
+  sub isFat($);
+  sub isMachO($);
+  sub isZip($);
+  sub lIsDir($);
+  sub lIsExecutable($);
+  sub lIsRegularFile($);
+  sub lIsSymLink($);
+  sub lstat($);
+  sub lstatMode($);
+  sub lstatType($);
+  sub magic($);
+  sub magic2($);
+  sub path($);
+  sub stat($);
+  sub statSize($);
+}
+
+%gConfig = (
+  'cmd_lipo' => 'lipo',
+  'cmd_rm'   => 'rm',
+);
+
+$gDryRun = 0;
+$gOnlyOne = 'copy';
+$gVerbosity = 2;
+@gSortMatches = ();
+
+Getopt::Long::Configure('pass_through');
+GetOptions('dry-run'           => \$gDryRun,
+           'only-one=s'        => \$gOnlyOne,
+           'verbosity=i'       => \$gVerbosity,
+           'unify-with-sort=s' => \@gSortMatches,
+           'config=s'          => \%gConfig); # "hidden" option not in usage()
+
+if (scalar(@ARGV) != 3 || $gVerbosity < 0 || $gVerbosity > 3 ||
+    ($gOnlyOne ne 'skip' && $gOnlyOne ne 'copy' && $gOnlyOne ne 'fail')) {
+  usage();
+  exit(1);
+}
+
+if (!makeUniversal($ARGV[0],$ARGV[1],$ARGV[2])) {
+  # makeUniversal or something it called will have printed an error.
+  exit(1);
+}
+
+exit(0);
+
+# argumentEscape(@arguments)
+#
+# Takes a list of @arguments and makes them shell-safe.
+sub argumentEscape(@) {
+  my (@arguments);
+  @arguments = @_;
+
+  my ($argument, @argumentsOut);
+  foreach $argument (@arguments) {
+    $argument =~ s%([^A-Za-z0-9_\-/.=+,])%\\$1%g;
+    push(@argumentsOut, $argument);
+  }
+
+  return @argumentsOut;
+}
+
+# command(@arguments)
+#
+# Runs the specified command by calling system(@arguments).  If $gDryRun
+# is true, the command is printed but not executed, and 0 is returned.
+# if $gVerbosity is greater than 1, the command is printed before being
+# executed.  When the command is executed, the system() return value will
+# be returned.  stdout and stderr are left connected for command output.
+sub command(@) {
+  my (@arguments);
+  @arguments = @_;
+  if ($gVerbosity >= 3 || $gDryRun) {
+    print(join(' ', argumentEscape(@arguments))."\n");
+  }
+  if ($gDryRun) {
+    return 0;
+  }
+  return system(@arguments);
+}
+
+# compareZipArchives($zip1, $zip2)
+#
+# Given two pathnames to zip archives, determines whether or not they are
+# functionally identical.  Returns true if they are, false if they differ in
+# some substantial way, and undef if an error occurs.  If the zip files
+# differ, diagnostic messages are printed indicating how they differ.
+#
+# Zip files will differ if any of the members are different as defined by
+# readZipCRCs, which consider CRCs, sizes, and file types as stored in the
+# file header.  Timestamps are not considered.  Zip files also differ if one
+# file contains members that the other one does not.  $gOnlyOne has no
+# effect on this behavior.
+sub compareZipArchives($$) {
+  my ($zip1, $zip2);
+  ($zip1, $zip2) = @_;
+
+  my ($CRCHash1, $CRCHash2);
+  if (!defined($CRCHash1 = readZipCRCs($zip1))) {
+    # readZipCRCs printed an error.
+    return undef;
+  }
+  if (!defined($CRCHash2 = readZipCRCs($zip2))) {
+    # readZipCRCs printed an error.
+    return undef;
+  }
+
+  my (@diffCRCs, @onlyInZip1);
+  @diffCRCs = ();
+  @onlyInZip1 = ();
+
+  my ($memberName);
+  foreach $memberName (keys(%$CRCHash1)) {
+    if (!exists($$CRCHash2{$memberName})) {
+      # The member is present in $zip1 but not $zip2.
+      push(@onlyInZip1, $memberName);
+    }
+    elsif ($$CRCHash1{$memberName} ne $$CRCHash2{$memberName}) {
+      # The member is present in both archives but its CRC or some other
+      # other critical attribute isn't identical.
+      push(@diffCRCs, $memberName);
+    }
+    delete($$CRCHash2{$memberName});
+  }
+
+  # If any members remain in %CRCHash2, it's because they're not present
+  # in $zip1.
+  my (@onlyInZip2);
+  @onlyInZip2 = keys(%$CRCHash2);
+
+  if (scalar(@onlyInZip1) + scalar(@onlyInZip2) + scalar(@diffCRCs)) {
+    complain(1, 'compareZipArchives: zip archives differ:',
+             $zip1,
+             $zip2);
+    if (scalar(@onlyInZip1)) {
+      complain(1, 'compareZipArchives: members only in former:',
+               @onlyInZip1);
+    }
+    if (scalar(@onlyInZip2)) {
+      complain(1, 'compareZipArchives: members only in latter:',
+               @onlyInZip2);
+    }
+    if (scalar(@diffCRCs)) {
+      complain(1, 'compareZipArchives: members differ:',
+               @diffCRCs);
+    }
+    return 0;
+  }
+
+  return 1;
+}
+
+# complain($severity, $message, @list)
+#
+# Prints $message to stderr if $gVerbosity allows it for severity level
+# $severity.  @list is a list of words that will be shell-escaped and printed
+# after $message, one per line, intended to be used, for example, to list
+# arguments to a call that failed.
+#
+# Expected severity levels are 1 for hard errors and 2 for non-fatal warnings.
+#
+# Always returns false as a convenience, so callers can return complain's
+# return value when it is used to signal errors.
+sub complain($$@) {
+  my ($severity, $message, @list);
+  ($severity, $message, @list) = @_;
+
+  if ($gVerbosity >= $severity) {
+    print STDERR ($0.': '.$message."\n");
+
+    my ($item);
+    while ($item = shift(@list)) {
+      print STDERR ('  '.(argumentEscape($item))[0].
+                    (scalar(@list)?',':'')."\n");
+    }
+  }
+
+  return 0;
+}
+
+# copyIfIdentical($source1, $source2, $target)
+#
+# $source1 and $source2 are FileAttrCache objects that are compared, and if
+# identical, copied to path string $target.  The comparison is initially
+# done as a byte-for-byte comparison, but if the files differ and appear to
+# be zip archives, compareZipArchives is called to determine whether
+# files that are not byte-for-byte identical are equivalent archives.
+#
+# Returns true on success, false for files that are not identical or
+# equivalent archives, and undef if an error occurs.
+#
+# One of $source1 and $source2 is permitted to be undef.  In this event,
+# whichever source is defined is copied directly to $target without performing
+# any comparisons.  This enables the $gOnlyOne = 'copy' mode, which is
+# driven by makeUniversalDirectory and makeUniversalInternal.
+sub copyIfIdentical($$$) {
+  my ($source1, $source2, $target);
+  ($source1, $source2, $target) = @_;
+
+  if (!defined($source1)) {
+    # If there's only one source file, make it the first file.  Order
+    # isn't important here, and this makes it possible to use
+    # defined($source2) as the switch, and to always copy from $source1.
+    $source1 = $source2;
+    $source2 = undef;
+  }
+
+  if (defined($source2)) {
+    # Only do the comparisons if there are two source files.  If there's
+    # only one source file, skip the comparisons and go straight to the
+    # copy operation.
+    if ($gVerbosity >= 3 || $gDryRun) {
+      print('cmp -s '.
+            join(' ',argumentEscape($source1->path(), $source2->path()))."\n");
+    }
+    my ($comparison);
+    if (!defined($comparison = compare($source1->path(), $source2->path())) ||
+        $comparison == -1) {
+      return complain(1, 'copyIfIdentical: compare: '.$!.' while comparing:',
+                      $source1->path(),
+                      $source2->path());
+    }
+    elsif ($comparison != 0) {
+      my ($zip1, $zip2);
+      if (defined($zip1 = $source1->isZip()) &&
+          defined($zip2 = $source2->isZip()) &&
+          $zip1 && $zip2) {
+        my ($zipComparison);
+        if (!defined($zipComparison = compareZipArchives($source1->path(),
+                                                         $source2->path)) ||
+            !$zipComparison) {
+          # An error occurred or the zip files aren't sufficiently identical.
+          # compareZipArchives will have printed an error message.
+          return 0;
+        }
+        # The zip files were compared successfully, and they both contain
+        # all of the same members, and all of their members' CRCs are
+        # identical.  For the purposes of this script, the zip files can be
+        # treated as identical, so reset $comparison.
+        $comparison = 0;
+      }
+    }
+    if ($comparison != 0) {
+      return complain(1, 'copyIfIdentical: files differ:',
+                      $source1->path(),
+                      $source2->path());
+    }
+  }
+
+  if ($gVerbosity >= 3 || $gDryRun) {
+    print('cp '.
+          join(' ',argumentEscape($source1->path(), $target))."\n");
+  }
+
+  if (!$gDryRun) {
+    my ($isExecutable);
+
+    # Set the execute bits (as allowed by the umask) on the new file if any
+    # execute bit is set on either old file.
+    $isExecutable = $source1->lIsExecutable() ||
+                    (defined($source2) && $source2->lIsExecutable());
+
+    if (!createUniqueFile($target, $isExecutable ? 0777 : 0666)) {
+      # createUniqueFile printed an error.
+      return 0;
+    }
+
+    if (!copy($source1->path(), $target)) {
+      complain(1, 'copyIfIdentical: copy: '.$!.' while copying',
+               $source1->path(),
+               $target);
+      unlink($target);
+      return 0;
+    }
+  }
+
+  return 1;
+}
+
+# slurp($file)
+#
+# Read the contents of $file into an array and return it.
+# Returns undef on error.
+sub slurp($) {
+  my $file = $_[0];
+  open FILE, $file or return undef;
+  my @lines = <FILE>;
+  close FILE;
+  return @lines;
+}
+
+# get_sorted($file)
+# Get the sorted lines of a file as a list, normalizing a newline on the last line if necessary.
+sub get_sorted($) {
+  my ($file) = @_;
+  my @lines = slurp($file);
+  my $lastline = $lines[-1];
+  if (!($lastline =~ /\n/)) {
+    $lines[-1] = $lastline . "\n";
+  }
+  return sort(@lines);
+}
+
+# compare_sorted($file1, $file2)
+#
+# Read the contents of both files into arrays, sort the arrays,
+# and then compare the two arrays for equality.
+#
+# Returns 0 if the sorted array contents are equal, or 1 if not.
+# Returns undef on error.
+sub compare_sorted($$) {
+  my ($file1, $file2) = @_;
+  my @lines1 = get_sorted($file1);
+  my @lines2 = get_sorted($file2);
+
+  return undef if !@lines1 || !@lines2;
+  return 1 unless scalar @lines1 == scalar @lines2;
+
+  for (my $i = 0; $i < scalar @lines1; $i++) {
+    return 1 if $lines1[$i] ne $lines2[$i];
+  }
+  return 0;
+}
+
+# copyIfIdenticalWhenSorted($source1, $source2, $target)
+#
+# $source1 and $source2 are FileAttrCache objects that are compared, and if
+# identical, copied to path string $target.  The comparison is done by
+# sorting the individual lines within the two files and comparing the results.
+#
+# Returns true on success, false for files that are not equivalent,
+# and undef if an error occurs.
+sub copyIfIdenticalWhenSorted($$$) {
+  my ($source1, $source2, $target);
+  ($source1, $source2, $target) = @_;
+
+  if ($gVerbosity >= 3 || $gDryRun) {
+    print('cmp -s '.
+          join(' ',argumentEscape($source1->path(), $source2->path()))."\n");
+  }
+  my ($comparison);
+  if (!defined($comparison = compare_sorted($source1->path(),
+                                            $source2->path())) ||
+      $comparison == -1) {
+    return complain(1, 'copyIfIdenticalWhenSorted: compare: '.$!
+                    .' while comparing:',
+                      $source1->path(),
+                      $source2->path());
+  }
+  if ($comparison != 0) {
+    return complain(1, 'copyIfIdenticalWhenSorted: files differ:',
+                    $source1->path(),
+                    $source2->path());
+  }
+
+  if ($gVerbosity >= 3 || $gDryRun) {
+    print('cp '.
+          join(' ',argumentEscape($source1->path(), $target))."\n");
+  }
+
+  if (!$gDryRun) {
+    my ($isExecutable);
+
+    # Set the execute bits (as allowed by the umask) on the new file if any
+    # execute bit is set on either old file.
+    $isExecutable = $source1->lIsExecutable() ||
+                    (defined($source2) && $source2->lIsExecutable());
+
+    if (!createUniqueFile($target, $isExecutable ? 0777 : 0666)) {
+      # createUniqueFile printed an error.
+      return 0;
+    }
+
+    if (!copy($source1->path(), $target)) {
+      complain(1, 'copyIfIdenticalWhenSorted: copy: '.$!
+               .' while copying',
+               $source1->path(),
+               $target);
+      unlink($target);
+      return 0;
+    }
+  }
+
+  return 1;
+}
+
+# createUniqueFile($path, $mode)
+#
+# Creates a new plain empty file at pathname $path, provided it does not
+# yet exist.  $mode is used as the file mode.  The actual file's mode will
+# be modified by the effective umask.  Returns false if the file could
+# not be created, setting $! to the error.  An error message is printed
+# in the event of failure.
+sub createUniqueFile($$) {
+  my ($path, $mode);
+  ($path, $mode) = @_;
+
+  my ($fh);
+  if (!sysopen($fh, $path, O_WRONLY | O_CREAT | O_EXCL, $mode)) {
+    return complain(1, 'createUniqueFile: open: '.$!.' for:',
+                    $path);
+  }
+  close($fh);
+
+  return 1;
+}
+
+# makeUniversal($pathPPC, $pathX86, $pathTarget)
+#
+# The top-level call.  $pathPPC, $pathX86, and $pathTarget are strings
+# identifying the ppc and x86 files or directories to merge and the location
+# to merge them to.  Returns false on failure and true on success.
+sub makeUniversal($$$) {
+  my ($pathTarget, $pathPPC, $pathX86);
+  ($pathPPC, $pathX86, $pathTarget) = @_;
+
+  my ($filePPC, $fileX86);
+  $filePPC = FileAttrCache->new($pathPPC);
+  $fileX86 = FileAttrCache->new($pathX86);
+
+  return makeUniversalInternal(1, $filePPC, $fileX86, $pathTarget);
+}
+
+# makeUniversalDirectory($dirPPC, $dirX86, $dirTarget)
+#
+# This is part of the heart of recursion.  $dirPPC and $dirX86 are
+# FileAttrCache objects designating the source ppc and x86 directories to
+# merge into a universal directory at $dirTarget, a string.  For each file
+# in $dirPPC and $dirX86, makeUniversalInternal is called.
+# makeUniversalInternal will call back into makeUniversalDirectory for
+# directories, thus completing the recursion.  If a failure is encountered
+# in ths function or in makeUniversalInternal or anything that it calls,
+# false is returned, otherwise, true is returned.
+#
+# If there are files present in one source directory but not both, the
+# value of $gOnlyOne controls the behavior.  If $gOnlyOne is 'copy', the
+# single source file is copied into $pathTarget.  If it is 'skip', it is
+# skipped.  If it is 'fail', such files will trigger makeUniversalDirectory
+# to fail.
+#
+# If either source directory is undef, it is treated as having no files.
+# This facilitates deep recursion when entire directories are only present
+# in one source when $gOnlyOne = 'copy'.
+sub makeUniversalDirectory($$$) {
+  my ($dirPPC, $dirX86, $dirTarget);
+  ($dirPPC, $dirX86, $dirTarget) = @_;
+
+  my ($dh, @filesPPC, @filesX86);
+
+  @filesPPC = ();
+  if (defined($dirPPC)) {
+    if (!opendir($dh, $dirPPC->path())) {
+      return complain(1, 'makeUniversalDirectory: opendir ppc: '.$!.' for:',
+                      $dirPPC->path());
+    }
+    @filesPPC = readdir($dh);
+    closedir($dh);
+  }
+
+  @filesX86 = ();
+  if (defined($dirX86)) {
+    if (!opendir($dh, $dirX86->path())) {
+      return complain(1, 'makeUniversalDirectory: opendir x86: '.$!.' for:',
+                      $dirX86->path());
+     }
+    @filesX86 = readdir($dh);
+    closedir($dh);
+  }
+
+  my (%common, $file, %onlyPPC, %onlyX86);
+
+  %onlyPPC = ();
+  foreach $file (@filesPPC) {
+    if ($file eq '.' || $file eq '..') {
+      next;
+    }
+    $onlyPPC{$file}=1;
+  }
+
+  %common = ();
+  %onlyX86 = ();
+  foreach $file (@filesX86) {
+    if ($file eq '.' || $file eq '..') {
+      next;
+    }
+    if ($onlyPPC{$file}) {
+      delete $onlyPPC{$file};
+      $common{$file}=1;
+    }
+    else {
+      $onlyX86{$file}=1;
+    }
+  }
+
+  # First, handle files common to both.
+  foreach $file (sort(keys(%common))) {
+    if (!makeUniversalInternal(0,
+                               FileAttrCache->new($dirPPC->path().'/'.$file),
+                               FileAttrCache->new($dirX86->path().'/'.$file),
+                               $dirTarget.'/'.$file)) {
+      # makeUniversalInternal will have printed an error.
+      return 0;
+    }
+  }
+
+  # Handle files found only in a single directory here.  There are three
+  # options, dictated by $gOnlyOne: fail if files are only present in
+  # one directory, skip any files only present in one directory, or copy
+  # these files straight over to the target directory.  In any event,
+  # a message will be printed indicating that the file trees don't match
+  # exactly.
+  if (keys(%onlyPPC)) {
+    complain(($gOnlyOne eq 'fail' ? 1 : 2),
+             ($gOnlyOne ne 'fail' ? 'warning: ' : '').
+             'makeUniversalDirectory: only in ppc '.
+             (argumentEscape($dirPPC->path()))[0].':',
+             argumentEscape(keys(%onlyPPC)));
+  }
+
+  if (keys(%onlyX86)) {
+    complain(($gOnlyOne eq 'fail' ? 1 : 2),
+             ($gOnlyOne ne 'fail' ? 'warning: ' : '').
+             'makeUniversalDirectory: only in x86 '.
+             (argumentEscape($dirX86->path()))[0].':',
+             argumentEscape(keys(%onlyX86)));
+  }
+
+  if ($gOnlyOne eq 'fail' && (keys(%onlyPPC) || keys(%onlyX86))) {
+    # Error message(s) printed above.
+    return 0;
+  }
+
+  if ($gOnlyOne eq 'copy') {
+    foreach $file (sort(keys(%onlyPPC))) {
+      if (!makeUniversalInternal(0,
+                                 FileAttrCache->new($dirPPC->path().'/'.$file),
+                                 undef,
+                                 $dirTarget.'/'.$file)) {
+        # makeUniversalInternal will have printed an error.
+        return 0;
+      }
+    }
+
+    foreach $file (sort(keys(%onlyX86))) {
+      if (!makeUniversalInternal(0,
+                                 undef,
+                                 FileAttrCache->new($dirX86->path().'/'.$file),
+                                 $dirTarget.'/'.$file)) {
+        # makeUniversalInternal will have printed an error.
+        return 0;
+      }
+    }
+  }
+
+  return 1;
+}
+
+# makeUniversalFile($sourcePPC, $sourceX86, $targetPath)
+#
+# Creates a universal file at pathname $targetPath based on a ppc image at
+# $sourcePPC and an x86 image at $sourceX86.  $sourcePPC and $sourceX86 are
+# both FileAttrCache objects.  Returns true on success and false on failure.
+# On failure, diagnostics will be printed to stderr.
+#
+# The source files may be either thin Mach-O images of the appropriate
+# architecture, or fat Mach-O files that contain images of the appropriate
+# architecture.
+#
+# This function wraps the lipo utility, see lipo(1).
+sub makeUniversalFile($$$) {
+  my ($sourcePPC, $sourceX86, $targetPath, @tempThinFiles, $thinPPC, $thinX86);
+  ($sourcePPC, $sourceX86, $targetPath) = @_;
+  $thinPPC = $sourcePPC;
+  $thinX86 = $sourceX86;
+
+  @tempThinFiles = ();
+
+  # The source files might already be fat.  They should be thinned out to only
+  # contain a single architecture.
+ 
+  my ($isFatPPC, $isFatX86);
+
+  if(!defined($isFatPPC = $sourcePPC->isFat())) {
+    # isFat printed its own error
+    return 0;
+  }
+  elsif($isFatPPC) {
+    $thinPPC = FileAttrCache->new($targetPath.'.ppc');
+    push(@tempThinFiles, $thinPPC->path());
+    if (command($gConfig{'cmd_lipo'}, '-thin', 'ppc',
+                $sourcePPC->path(), '-output', $thinPPC->path()) != 0) {
+      unlink(@tempThinFiles);
+      return complain(1, 'lipo thin ppc failed for:',
+                      $sourcePPC->path(),
+                      $thinPPC->path());
+    }
+  }
+
+  if(!defined($isFatX86 = $sourceX86->isFat())) {
+    # isFat printed its own error
+    unlink(@tempThinFiles);
+    return 0;
+  }
+  elsif($isFatX86) {
+    $thinX86 = FileAttrCache->new($targetPath.'.x86');
+    push(@tempThinFiles, $thinX86->path());
+    if (command($gConfig{'cmd_lipo'}, '-thin', 'i386',
+                $sourceX86->path(), '-output', $thinX86->path()) != 0) {
+      unlink(@tempThinFiles);
+      return complain(1, 'lipo thin x86 failed for:',
+                      $sourceX86->path(),
+                      $thinX86->path());
+    }
+  }
+
+  # The image for each architecture in the fat file will be aligned on
+  # a specific boundary, default 4096 bytes, see lipo(1) -segalign.
+  # Since there's no tail-padding, the fat file will consume the least
+  # space on disk if the image that comes last exceeds the segment size
+  # by the smallest amount.
+  #
+  # This saves an average of 1kB per fat file over the naive approach of
+  # always putting one architecture first: average savings is 2kB per
+  # file, but the naive approach would have gotten it right half of the
+  # time.
+
+  my ($sizePPC, $sizeX86, $thinPPCForStat, $thinX86ForStat);
+
+  if (!$gDryRun) {
+    $thinPPCForStat = $thinPPC;
+    $thinX86ForStat = $thinX86;
+  }
+  else {
+    # Normally, fat source files will have been converted into temporary
+    # thin files.  During a dry run, that doesn't happen, so fake it up
+    # a little bit by always using the source file, fat or thin, for the
+    # stat.
+    $thinPPCForStat = $sourcePPC;
+    $thinX86ForStat = $sourceX86;
+  }
+
+  if (!defined($sizePPC = $thinPPCForStat->statSize())) {
+    unlink(@tempThinFiles);
+    return complain(1, 'stat ppc: '.$!.' for:',
+                    $thinPPCForStat->path());
+  }
+  if (!defined($sizeX86 = $thinX86ForStat->statSize())) {
+    unlink(@tempThinFiles);
+    return complain(1, 'stat x86: '.$!.' for:',
+                    $thinX86ForStat->path());
+  }
+
+  $sizePPC = $sizePPC % 4096;
+  $sizeX86 = $sizeX86 % 4096;
+
+  my (@thinFiles);
+
+  if ($sizePPC == 0) {
+    # PPC image ends on an alignment boundary, there will be no padding before
+    # starting the x86 image.
+    @thinFiles = ($thinPPC->path(), $thinX86->path());
+  }
+  elsif ($sizeX86 == 0 || $sizeX86 > $sizePPC) {
+    # x86 image ends on an alignment boundary, there will be no padding before
+    # starting the PPC image, or the x86 image exceeds its alignment boundary
+    # by more than the PPC image, so there will be less padding if the x86
+    # comes first.
+    @thinFiles = ($thinX86->path(), $thinPPC->path());
+  }
+  else {
+    # PPC image exceeds its alignment boundary by more than the x86 image, so
+    # there will be less padding if the PPC comes first.
+    @thinFiles = ($thinPPC->path(), $thinX86->path());
+  }
+
+  my ($isExecutable);
+  $isExecutable = $sourcePPC->lIsExecutable() ||
+                  $sourceX86->lIsExecutable();
+
+  if (!$gDryRun) {
+    # Ensure that the file does not yet exist.
+
+    # Set the execute bits (as allowed by the umask) on the new file if any
+    # execute bit is set on either old file.  Yes, it is possible to have
+    # proper Mach-O files without x-bits: think object files (.o) and static
+    # archives (.a).
+    if (!createUniqueFile($targetPath, $isExecutable ? 0777 : 0666)) {
+      # createUniqueFile printed an error.
+      unlink(@tempThinFiles);
+      return 0;
+    }
+  }
+
+  # Create the fat file.
+  if (command($gConfig{'cmd_lipo'}, '-create', @thinFiles,
+              '-output', $targetPath) != 0) {
+    unlink(@tempThinFiles, $targetPath);
+    return complain(1, 'lipo create fat failed for:',
+                    @thinFiles,
+                    $targetPath);
+  }
+
+  unlink(@tempThinFiles);
+
+  if (!$gDryRun) {
+    # lipo seems to think that it's free to set its own file modes that
+    # ignore the umask, which is bogus when the rest of this script
+    # respects the umask.
+    if (!chmod(($isExecutable ? 0777 : 0666) & ~umask(), $targetPath)) {
+      complain(1, 'makeUniversalFile: chmod: '.$!.' for',
+               $targetPath);
+      unlink($targetPath);
+      return 0;
+    }
+  }
+
+  return 1;
+}
+
+# makeUniversalInternal($isToplevel, $filePPC, $fileX86, $fileTargetPath)
+#
+# Given FileAttrCache objects $filePPC and $fileX86, compares filetypes
+# and performs the appropriate action to produce a universal file at
+# path string $fileTargetPath.  $isToplevel should be true if this is
+# the recursive base and false otherwise; this controls cleanup behavior
+# (cleanup is only performed at the base, because cleanup itself is
+# recursive).
+#
+# This handles regular files by determining whether they are Mach-O files
+# and calling makeUniversalFile if so and copyIfIdentical otherwise.  Symbolic
+# links are handled directly in this function by ensuring that the source link
+# targets are identical and creating a new link with the same target
+# at $fileTargetPath.  Directories are handled by calling
+# makeUniversalDirectory.
+#
+# One of $filePPC and $fileX86 is permitted to be undef.  In that case,
+# the defined source file is copied directly to the target if a regular
+# file, and symlinked appropriately if a symbolic link.  This facilitates
+# use of $gOnlyOne = 'copy', although no $gOnlyOne checks are made in this
+# function, they are all handled in makeUniversalDirectory.
+#
+# Returns true on success.  Returns false on failure, including failures
+# in other functions called.
+sub makeUniversalInternal($$$$) {
+  my ($filePPC, $fileTargetPath, $fileX86, $isToplevel);
+  ($isToplevel, $filePPC, $fileX86, $fileTargetPath) = @_;
+
+  my ($typePPC, $typeX86);
+  if (defined($filePPC) && !defined($typePPC = $filePPC->lstatType())) {
+    return complain(1, 'makeUniversal: lstat ppc: '.$!.' for:',
+                    $filePPC->path());
+  }
+  if (defined($fileX86) && !defined($typeX86 = $fileX86->lstatType())) {
+    return complain(1, 'makeUniversal: lstat x86: '.$!.' for:',
+                    $fileX86->path());
+  }
+
+  if (defined($filePPC) && defined($fileX86) && $typePPC != $typeX86) {
+    return complain(1, 'makeUniversal: incompatible types:',
+                    $filePPC->path(),
+                    $fileX86->path());
+  }
+
+  # $aSourceFile will contain a FileAttrCache object that will return
+  # the correct type data.  It's used because it's possible for one of
+  # the two source files to be undefined (indicating a straight copy).
+  my ($aSourceFile);
+  if (defined($filePPC)) { 
+    $aSourceFile = $filePPC;
+  }
+  else {
+    $aSourceFile = $fileX86;
+  }
+
+  if ($aSourceFile->lIsDir()) {
+    if ($gVerbosity >= 3 || $gDryRun) {
+      print('mkdir '.(argumentEscape($fileTargetPath))[0]."\n");
+    }
+    if (!$gDryRun && !mkdir($fileTargetPath)) {
+      return complain(1, 'makeUniversal: mkdir: '.$!.' for:',
+                      $fileTargetPath);
+    }
+
+    my ($rv);
+
+    if (!($rv = makeUniversalDirectory($filePPC, $fileX86, $fileTargetPath))) {
+      # makeUniversalDirectory printed an error.
+      if ($isToplevel) {
+        command($gConfig{'cmd_rm'},'-rf','--',$fileTargetPath);
+      }
+    }
+    else {
+      # Touch the directory when leaving it.  If unify is being run on an
+      # .app bundle, the .app might show up without an icon because the
+      # system might have found the .app before it was completely built.
+      # Touching it dirties it in LaunchServices' mind.
+      if ($gVerbosity >= 3) {
+        print('touch '.(argumentEscape($fileTargetPath))[0]."\n");
+      }
+      utime(undef, undef, $fileTargetPath);
+    }
+
+    return $rv;
+  }
+  elsif ($aSourceFile->lIsSymLink()) {
+    my ($linkPPC, $linkX86);
+    if (defined($filePPC) && !defined($linkPPC=readlink($filePPC->path()))) {
+      return complain(1, 'makeUniversal: readlink ppc: '.$!.' for:',
+                      $filePPC->path());
+    }
+    if (defined($fileX86) && !defined($linkX86=readlink($fileX86->path()))) {
+      return complain(1, 'makeUniversal: readlink x86: '.$!.' for:',
+                      $fileX86->path());
+    }
+    if (defined($filePPC) && defined($fileX86) && $linkPPC ne $linkX86) {
+      return complain(1, 'makeUniversal: symbolic links differ:',
+                      $filePPC->path(),
+                      $fileX86->path());
+    }
+
+    # $aLink here serves the same purpose as $aSourceFile in the enclosing
+    # block: it refers to the target of the symbolic link, whether there
+    # is one valid source or two.
+    my ($aLink);
+    if (defined($linkPPC)) {
+      $aLink = $linkPPC;
+    }
+    else {
+      $aLink = $linkX86;
+    }
+
+    if ($gVerbosity >= 3 || $gDryRun) {
+      print('ln -s '.
+            join(' ',argumentEscape($aLink, $fileTargetPath))."\n");
+    }
+    if (!$gDryRun && !symlink($aLink, $fileTargetPath)) {
+      return complain(1, 'makeUniversal: symlink: '.$!.' for:',
+                      $aLink,
+                      $fileTargetPath);
+    }
+
+    return 1;
+  }
+  elsif($aSourceFile->lIsRegularFile()) {
+    my ($machPPC, $machX86, $fileName);
+    if (!defined($filePPC) || !defined($fileX86)) {
+      # One of the source files isn't present.  The right thing to do is
+      # to just copy what does exist straight over, so skip Mach-O checks.
+      $machPPC = 0;
+      $machX86 = 0;
+      if (defined($filePPC)) {
+        $fileName = $filePPC;
+      } elsif (defined($fileX86)) {
+        $fileName = $fileX86;
+      } else {
+        complain(1, "The file must exist in at least one directory");
+        exit(1);
+      }
+    }
+    else {
+      # both files exist, pick the name of one.
+      $fileName = $fileX86;
+      if (!defined($machPPC=$filePPC->isMachO())) {
+        return complain(1, 'makeUniversal: isFileMachO ppc failed for:',
+                        $filePPC->path());
+      }
+      if (!defined($machX86=$fileX86->isMachO())) {
+        return complain(1, 'makeUniversal: isFileMachO x86 failed for:',
+                        $fileX86->path());
+      }
+    }
+
+    if ($machPPC != $machX86) {
+      return complain(1, 'makeUniversal: variant Mach-O attributes:',
+                      $filePPC->path(),
+                  $fileX86->path());
+    }
+
+    if ($machPPC) {
+      # makeUniversalFile will print an error if it fails.
+      return makeUniversalFile($filePPC, $fileX86, $fileTargetPath);
+    }
+
+    if (grep { $fileName->path() =~ m/$_/; } @gSortMatches) {
+      # Regular files, but should be compared with sorting first.
+      # copyIfIdenticalWhenSorted will print an error if it fails.
+      return copyIfIdenticalWhenSorted($filePPC, $fileX86, $fileTargetPath);
+    }
+
+    # Regular file.  copyIfIdentical will print an error if it fails.
+    return copyIfIdentical($filePPC, $fileX86, $fileTargetPath);
+  }
+
+  # Special file, don't know how to handle.
+  return complain(1, 'makeUniversal: cannot handle special file:',
+                  $filePPC->path(),
+                  $fileX86->path());
+}
+
+# usage()
+#
+# Give the user a hand.
+sub usage() {
+  print STDERR (
+"usage: unify <ppc-path> <x86-path> <universal-path>\n".
+"            [--dry-run]           (print what would be done)\n".
+"            [--only-one <action>] (skip, copy, fail; default=copy)\n".
+"            [--verbosity <level>] (0, 1, 2, 3; default=2)\n");
+  return;
+}
+
+# readZipCRCs($zipFile)
+#
+# $zipFile is the pathname to a zip file whose directory will be read.
+# A reference to a hash is returned, with the member pathnames from the
+# zip file as keys, and reasonably unique identifiers as values.  The
+# format of the values is not specified exactly, but does include the
+# member CRCs and sizes and differentiates between files and directories.
+# It specifically does not distinguish between modification times.  On
+# failure, prints a message and returns undef.
+sub readZipCRCs($) {
+  my ($zipFile);
+  ($zipFile) = @_;
+
+  my ($ze, $zip);
+  $zip = Archive::Zip->new();
+
+  if (($ze = $zip->read($zipFile)) != AZ_OK) {
+    complain(1, 'readZipCRCs: read error '.$ze.' for:',
+             $zipFile);
+    return undef;
+  }
+
+  my ($member, %memberCRCs, @memberList);
+  %memberCRCs = ();
+  @memberList = $zip->members();
+
+  foreach $member (@memberList) {
+    # Take a few of the attributes that identify the file and stuff them into
+    # the members hash.  Directories will show up with size 0 and crc32 0,
+    # so isDirectory() is used to distinguish them from empty files.
+    $memberCRCs{$member->fileName()} = join(',', $member->isDirectory() ? 1 : 0,
+                                                 $member->uncompressedSize(),
+                                                 $member->crc32String());
+  }
+
+  return {%memberCRCs};
+}
+
+{
+  # FileAttrCache allows various attributes about a file to be cached
+  # so that if they are needed again after first use, no system calls
+  # will be made and the program won't need to hit the disk.
+
+  package FileAttrCache;
+
+  # from /usr/include/mach-o/loader.h
+  use constant MH_MAGIC    => 0xfeedface;
+  use constant MH_CIGAM    => 0xcefaedfe;
+  use constant MH_MAGIC_64 => 0xfeedfacf;
+  use constant MH_CIGAM_64 => 0xcffaedfe;
+
+  use Fcntl(':DEFAULT', ':mode');
+
+  # FileAttrCache->new($path)
+  #
+  # Creates a new FileAttrCache object for the file at path $path and
+  # returns it.  The cache is not primed at creation time, values are
+  # fetched lazily as they are needed.
+  sub new($$) {
+    my ($class, $path, $proto, $this);
+    ($proto, $path) = @_;
+    if (!($class = ref($proto))) {
+      $class = $proto;
+    }
+    $this = {
+      'path'        => $path,
+      'lstat'       => undef,
+      'lstatErrno'  => 0,
+      'lstatInit'   => 0,
+      'magic'       => undef,
+      'magic2'       => undef,
+      'magicErrno'  => 0,
+      'magicErrMsg' => undef,
+      'magicInit'   => 0,
+      'stat'        => undef,
+      'statErrno'   => 0,
+      'statInit'    => 0,
+    };
+    bless($this, $class);
+    return($this);
+  }
+
+  # $FileAttrCache->isFat()
+  #
+  # Returns true if the file is a fat Mach-O file, false if it's not, and
+  # undef if an error occurs.  See /usr/include/mach-o/fat.h.
+  sub isFat($) {
+    my ($magic, $magic2, $this);
+    ($this) = @_;
+
+    # magic() caches, there's no separate cache because isFat() doesn't hit
+    # the disk other than by calling magic().
+
+    if (!defined($magic = $this->magic())) {
+      return undef;
+    }
+    $magic2 = $this->magic2();
+
+    # We have to sanity check the second four bytes, because Java class
+    # files use the same magic number as Mach-O fat binaries.
+    # This logic is adapted from file(1), which says that Mach-O uses
+    # these bytes to count the number of architectures within, while
+    # Java uses it for a version number. Conveniently, there are only
+    # 18 labelled Mach-O architectures, and Java's first released
+    # class format used the version 43.0.
+    if ($magic == 0xcafebabe && $magic2 < 20) {
+      return 1;
+    }
+
+    return 0;
+  }
+
+  # $FileAttrCache->isMachO()
+  #
+  # Returns true if the file is a Mach-O image (including a fat file), false
+  # if it's not, and undef if an error occurs.  See
+  # /usr/include/mach-o/loader.h and /usr/include/mach-o/fat.h.
+  sub isMachO($) {
+    my ($magic, $this);
+    ($this) = @_;
+
+    # magic() caches, there's no separate cache because isMachO() doesn't hit
+    # the disk other than by calling magic().
+
+    if (!defined($magic = $this->magic())) {
+      return undef;
+    }
+
+    # Accept Mach-O fat files or Mach-O thin files of either endianness.
+    if ($magic == MH_MAGIC ||
+        $magic == MH_CIGAM ||
+        $magic == MH_MAGIC_64 ||
+        $magic == MH_CIGAM_64 ||
+        $this->isFat()) {
+      return 1;
+    }
+
+    return 0;
+  }
+
+  # $FileAttrCache->isZip()
+  #
+  # Returns true if the file is a zip file, false if it's not, and undef if
+  # an error occurs.  See http://www.pkware.com/business_and_developers/developer/popups/appnote.txt .
+  sub isZip($) {
+    my ($magic, $this);
+    ($this) = @_;
+
+    # magic() caches, there's no separate cache because isFat() doesn't hit
+    # the disk other than by calling magic().
+
+    if (!defined($magic = $this->magic())) {
+      return undef;
+    }
+
+    if ($magic == 0x504b0304) {
+      return 1;
+    }
+
+    return 0;
+  }
+
+  # $FileAttrCache->lIsExecutable()
+  #
+  # Wraps $FileAttrCache->lstat(), returning true if the file is has any,
+  # execute bit set, false if none are set, or undef if an error occurs.
+  # On error, $! is set to lstat's errno.
+  sub lIsExecutable($) {
+    my ($mode, $this);
+    ($this) = @_;
+
+    if (!defined($mode = $this->lstatMode())) {
+      return undef;
+    }
+
+    return $mode & (S_IXUSR | S_IXGRP | S_IXOTH);
+  }
+
+  # $FileAttrCache->lIsDir()
+  #
+  # Wraps $FileAttrCache->lstat(), returning true if the file is a directory,
+  # false if it isn't, or undef if an error occurs.  Because lstat is used,
+  # this will return false even if the file is a symlink pointing to a
+  # directory.  On error, $! is set to lstat's errno.
+  sub lIsDir($) {
+    my ($type, $this);
+    ($this) = @_;
+
+    if (!defined($type = $this->lstatType())) {
+      return undef;
+    }
+
+    return S_ISDIR($type);
+  }
+
+  # $FileAttrCache->lIsRegularFile()
+  #
+  # Wraps $FileAttrCache->lstat(), returning true if the file is a regular,
+  # file, false if it isn't, or undef if an error occurs.  Because lstat is
+  # used, this will return false even if the file is a symlink pointing to a
+  # regular file.  On error, $! is set to lstat's errno.
+  sub lIsRegularFile($) {
+    my ($type, $this);
+    ($this) = @_;
+
+    if (!defined($type = $this->lstatType())) {
+      return undef;
+    }
+
+    return S_ISREG($type);
+  }
+
+  # $FileAttrCache->lIsSymLink()
+  #
+  # Wraps $FileAttrCache->lstat(), returning true if the file is a symbolic,
+  # link, false if it isn't, or undef if an error occurs.  On error, $! is
+  # set to lstat's errno.
+  sub lIsSymLink($) {
+    my ($type, $this);
+    ($this) = @_;
+   
+    if (!defined($type = $this->lstatType())) {
+      return undef;
+    }
+
+    return S_ISLNK($type);
+  }
+
+  # $FileAttrCache->lstat()
+  #
+  # Wraps the lstat system call, providing a cache to speed up multiple
+  # lstat calls for the same file.  See lstat(2) and lstat in perlfunc(1).
+  sub lstat($) {
+    my (@stat, $this);
+    ($this) = @_;
+
+    # Use the cached lstat result.
+    if ($$this{'lstatInit'}) {
+      if (defined($$this{'lstatErrno'})) {
+        $! = $$this{'lstatErrno'};
+      }
+      return @{$$this{'lstat'}};
+    }
+    $$this{'lstatInit'} = 1;
+
+    if (!(@stat = CORE::lstat($$this{'path'}))) {
+      $$this{'lstatErrno'} = $!;
+    }
+
+    $$this{'lstat'} = [@stat];
+    return @stat;
+  }
+
+  # $FileAttrCache->lstatMode()
+  #
+  # Wraps $FileAttrCache->lstat(), returning the mode bits from the st_mode
+  # field, or undef if an error occurs.  On error, $! is set to lstat's
+  # errno.
+  sub lstatMode($) {
+    my (@stat, $this);
+    ($this) = @_;
+
+    if (!(@stat = $this->lstat())) {
+      return undef;
+    }
+
+    return S_IMODE($stat[2]);
+  }
+
+  # $FileAttrCache->lstatType()
+  #
+  # Wraps $FileAttrCache->lstat(), returning the type bits from the st_mode
+  # field, or undef if an error occurs.  On error, $! is set to lstat's
+  # errno.
+  sub lstatType($) {
+    my (@stat, $this);
+    ($this) = @_;
+
+    if (!(@stat = $this->lstat())) {
+      return undef;
+    }
+
+    return S_IFMT($stat[2]);
+  }
+
+  # $FileAttrCache->magic()
+  #
+  # Returns the "magic number" for the file by reading its first four bytes
+  # as a big-endian unsigned 32-bit integer and returning the result.  If an
+  # error occurs, returns undef and prints diagnostic messages to stderr.  If
+  # the file is shorter than 32 bits, returns -1.  A cache is provided to
+  # speed multiple magic calls for the same file.
+  sub magic($) {
+    my ($this);
+    ($this) = @_;
+
+    # Use the cached magic result.
+    if ($$this{'magicInit'}) {
+      if (defined($$this{'magicErrno'})) {
+        if (defined($$this{'magicErrMsg'})) {
+          main::complain(1, 'FileAttrCache::magic: '.$$this{'magicErrMsg'}.' for:',
+                   $$this{'path'});
+        }
+        $! = $$this{'magicErrno'};
+      }
+      return $$this{'magic'};
+    }
+
+    $$this{'magicInit'} = 1;
+
+    my ($fh);
+    if (!sysopen($fh, $$this{'path'}, O_RDONLY)) {
+      $$this{'magicErrno'} = $!;
+      $$this{'magicErrMsg'} = 'open "'.$$this{'path'}.'": '.$!;
+      main::complain(1, 'FileAttrCache::magic: '.$$this{'magicErrMsg'}.' for:',
+               $$this{'path'});
+      return undef;
+    }
+
+    $! = 0;
+    my ($bytes, $magic, $bytes2, $magic2);
+    if (!defined($bytes = sysread($fh, $magic, 4))) {
+      $$this{'magicErrno'} = $!;
+      $$this{'magicErrMsg'} = 'read "'.$$this{'path'}.'": '.$!;
+      main::complain(1, 'FileAttrCache::magic: '.$$this{'magicErrMsg'}.' for:',
+               $$this{'path'});
+      close($fh);
+      return undef;
+    }
+    else {
+      $bytes2 = sysread($fh, $magic2, 4);
+    }
+
+    close($fh);
+
+    if ($bytes != 4) {
+      # The file is too short, didn't read a magic number.  This isn't really
+      # an error.  Return an unlikely value.
+      $$this{'magic'} = -1;
+      $$this{'magic2'} = -1;
+      return -1;
+    }
+    if ($bytes2 != 4) {
+      # File is too short to read a second 4 bytes.
+      $magic2 = -1;
+    }
+
+    $$this{'magic'} = unpack('N', $magic);
+    $$this{'magic2'} = unpack('N', $magic2);
+    return $$this{'magic'};
+  }
+
+  # $FileAttrCache->magic2()
+  #
+  # Returns the second four bytes of the file as a 32-bit little endian number.
+  # See magic(), above for more info.
+  sub magic2($) {
+    my ($this);
+    ($this) = @_;
+
+    # we do the actual work (and cache it) in magic().
+    if (!$$this{'magicInit'}) {
+      my $magic = $$this->magic();
+    }
+
+    return $$this{'magic2'};
+  }
+
+  # $FileAttrCache->path()
+  #
+  # Returns the file's pathname.
+  sub path($) {
+    my ($this);
+    ($this) = @_;
+    return $$this{'path'};
+  }
+
+  # $FileAttrCache->stat()
+  #
+  # Wraps the stat system call, providing a cache to speed up multiple
+  # stat calls for the same file.  If lstat() has already been called and
+  # the file is not a symbolic link, the cached lstat() result will be used.
+  # See stat(2) and lstat in perlfunc(1).
+  sub stat($) {
+    my (@stat, $this);
+    ($this) = @_;
+
+    # Use the cached stat result.
+    if ($$this{'statInit'}) {
+      if (defined($$this{'statErrno'})) {
+        $! = $$this{'statErrno'};
+      }
+      return @{$$this{'stat'}};
+    }
+
+    $$this{'statInit'} = 1;
+
+    # If lstat has already been called, and the file isn't a symbolic link,
+    # use the cached lstat result.
+    if ($$this{'lstatInit'} && !$$this{'lstatErrno'} &&
+        !S_ISLNK(${$$this{'lstat'}}[2])) {
+      $$this{'stat'} = $$this{'lstat'};
+      return @{$$this{'stat'}};
+    }
+
+    if (!(@stat = CORE::stat($$this{'path'}))) {
+      $$this{'statErrno'} = $!;
+    }
+
+    $$this{'stat'} = [@stat];
+    return @stat;
+  }
+
+  # $FileAttrCache->statSize()
+  #
+  # Wraps $FileAttrCache->stat(), returning the st_size field, or undef
+  # undef if an error occurs.  On error, $! is set to stat's errno.
+  sub statSize($) {
+    my (@stat, $this);
+    ($this) = @_;
+
+    if (!(@stat = $this->lstat())) {
+      return undef;
+    }
+
+    return $stat[7];
+  }
+}