[SDL] Mac OS X Universal Binaries

[Christian Walther]

You could check the version of libSystem.B.dylib it links to (and you 
don't need to split the binary for that, otool has an '-arch' option):

buia:~ cwalther$ otool -L 
/Developer/SDKs/MacOSX10.2.8.sdk/usr/lib/libSystem.B.dylib
/Developer/SDKs/MacOSX10.2.8.sdk/usr/lib/libSystem.B.dylib:
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, 
current version 63.0.0)
         /usr/lib/system/libmathCommon.A.dylib (compatibility version 
1.0.0, current version 40.1.0)
buia:~ cwalther$ otool -L 
/Developer/SDKs/MacOSX10.3.9.sdk/usr/lib/libSystem.B.dylib
/Developer/SDKs/MacOSX10.3.9.sdk/usr/lib/libSystem.B.dylib:
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, 
current version 71.1.3)
         /usr/lib/system/libmathCommon.A.dylib (compatibility version 
1.0.0, current version 47.1.0)
buia:~ cwalther$ otool -L 
/Developer/SDKs/MacOSX10.4u.sdk/usr/lib/libSystem.B.dylib
/Developer/SDKs/MacOSX10.4u.sdk/usr/lib/libSystem.B.dylib:
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, 
current version 88.3.3)
         /usr/lib/system/libmathCommon.A.dylib (compatibility version 
1.0.0, current version 220.0.0)
buia:~ cwalther$ otool -L -arch ppc /Library/Frameworks/SDL.framework/SDL
/Library/Frameworks/SDL.framework/SDL:
...
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, 
current version 63.0.0)
buia:~ cwalther$ otool -L -arch i386 /Library/Frameworks/SDL.framework/SDL
/Library/Frameworks/SDL.framework/SDL:
...
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, 
current version 88.1.3)

But that's probably not a sure-fire way of determining system 
compatibility. I think I've seen binaries that ran on 10.2.8 even though 
they were linked against later versions of libSystem.B.dylib.

  -Christian