--- a/build/Makefile.in
+++ b/build/Makefile.in
@@ -96,15 +96,52 @@ libs:: bloaturls.txt
 # of bloaturls.txt.  This is for browsers that can't do -f
 # autocycling of URLs.
 libs:: bloatcycle.html
 	$(INSTALL) $< $(DIST)/bin/res
 
 ifeq ($(OS_ARCH),Darwin)
 libs:: $(topsrcdir)/tools/rb/fix-macosx-stack.pl
 	$(INSTALL) $< $(DIST)/bin
+
+# Basic unit tests for some stuff in the unify script
+check::
+# build ppc/i386 binaries, and unify them
+	rm -f unify-test-ppc unify-test-i386 unify-test-universal
+	$(HOST_CC) -arch ppc $(srcdir)/unify-test.c -o unify-test-ppc
+	$(HOST_CC) -arch i386 $(srcdir)/unify-test.c -o unify-test-i386
+	@if ! $(srcdir)/macosx/universal/unify ./unify-test-ppc ./unify-test-i386 \
+          ./unify-test-universal; then \
+          echo "TEST-UNEXPECTED-FAIL | build/ | unify failed to produce a universal binary!"; \
+          false; \
+        fi
+	@if ! test -f ./unify-test-universal; then \
+          echo "TEST-UNEXPECTED-FAIL | build/ | unify failed to produce a universal binary!"; \
+          false; \
+        fi
+	@if ! file -b ./unify-test-universal | head -n1 | grep -q "^Mach-O universal binary"; then \
+          echo "TEST-UNEXPECTED-FAIL | build/ | unify failed to produce a universal binary!"; \
+          false; \
+        fi
+# try unifying two identical Java class files
+	rm -f unifytesta.class unifytestb.class unifytestc.class
+	cp $(srcdir)/unifytest.class ./unifytesta.class
+	cp $(srcdir)/unifytest.class ./unifytestb.class
+	@if ! $(srcdir)/macosx/universal/unify ./unifytesta.class ./unifytestb.class \
+          ./unifytestc.class; then \
+          echo "TEST-UNEXPECTED-FAIL | build/ | unify failed to unify a Java class file!"; \
+          false; \
+        fi
+	@if ! test -f ./unifytestc.class; then \
+          echo "TEST-UNEXPECTED-FAIL | build/ | unify failed to unify a Java class file!"; \
+          false; \
+        fi
+	@if ! diff -q ./unifytesta.class ./unifytestc.class; then \
+          echo "TEST-UNEXPECTED-FAIL | build/ | unify failed to unify a Java class file!"; \
+          false; \
+        fi
 endif
 
 ifeq ($(OS_ARCH),Linux)
 libs:: $(topsrcdir)/tools/rb/fix-linux-stack.pl
 	$(INSTALL) $< $(DIST)/bin
 endif
-endif
+endif # ENABLE_TESTS

--- a/build/macosx/universal/unify
+++ b/build/macosx/universal/unify
@@ -209,16 +209,17 @@ sub readZipCRCs($);
   sub lIsDir($);
   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',
@@ -1048,43 +1049,52 @@ sub readZipCRCs($) {
       $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, $this);
+    my ($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();
 
-    if ($magic == 0xcafebabe) {
+    # We have to sanity check the second four bytes, because Java class
+    # files use the same magic number as Mach-O fat binaries.
+    # This logic is adapted from file(1), which says that Mach-O uses
+    # these bytes to count the number of architectures within, while
+    # Java uses it for a version number. Conveniently, there are only
+    # 18 labelled Mach-O architectures, and Java's first released
+    # class format used the version 43.0.
+    if ($magic == 0xcafebabe && $magic2 < 20) {
       return 1;
     }
 
     return 0;
   }
 
   # $FileAttrCache->isMachO()
   #
@@ -1100,17 +1110,17 @@ sub readZipCRCs($) {
 
     if (!defined($magic = $this->magic())) {
       return undef;
     }
 
     # Accept Mach-O fat files or Mach-O thin files of either endianness.
     if ($magic == 0xfeedface ||
         $magic == 0xcefaedfe ||
-        $magic == 0xcafebabe) {
+        $this->isFat()) {
       return 1;
     }
 
     return 0;
   }
 
   # $FileAttrCache->isZip()
   #
@@ -1287,39 +1297,64 @@ sub readZipCRCs($) {
       $$this{'magicErrno'} = $!;
       $$this{'magicErrMsg'} = 'open "'.$$this{'path'}.'": '.$!;
       complain(1, 'FileAttrCache::magic: '.$$this{'magicErrMsg'}.' for:',
                $$this{'path'});
       return undef;
     }
 
     $! = 0;
-    my ($bytes, $magic);
+    my ($bytes, $magic, $bytes2, $magic2);
     if (!defined($bytes = sysread($fh, $magic, 4))) {
       $$this{'magicErrno'} = $!;
       $$this{'magicErrMsg'} = 'read "'.$$this{'path'}.'": '.$!;
       complain(1, 'FileAttrCache::magic: '.$$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'};
   }

new file mode 100644
--- /dev/null
+++ b/build/unify-test.c
@@ -0,0 +1,4 @@
+int main(int argc, char** argv)
+{
+  return 0;
+}

new file mode 100644
index 0000000000000000000000000000000000000000..7eca557ad5052ad004722bda39d3dcdf7e03c782
GIT binary patch
literal 263
zc${TUy9&ZU5S%s9Xna<Jg<u&i6l=vsunJlzHddE-%88y3FM^+CC0O_Yew4V0poI%F
zy9_hKK413-fIg}&ER-CS9aIRpq0-8X2$t7g672DDEeTa$X*rD#fs7U+*t23Egwlk%
zxAJ%5EP8vPx4pTEl->@KpgTXtQ79)WF;`-(HWwpLrkj{cu#qJczAB;iE13m585*>Z
s;lGl}FgO5yj;|(f;+^f>KvzBp4s$LQxfFTE$J$60{M#&MH*GGy0h(GaUH||9

new file mode 100644
--- /dev/null
+++ b/build/unifytest.java
@@ -0,0 +1,5 @@
+class unifytest {
+    public static void main(String[] args) {
+        return;
+    }
+}