macOS GCC complaining about undefined symbols when trying to compile for 10.5 in 10.6

foidulus said:

Code:

[COLOR="Red"]/usr/bin/gcc -Wall -O -dynamic -I/System/Library/Frameworks/JavaVM.framework/Headers -c -arch x86_64 QTMovieController.m QTMovieProcessor.m QTMovieViewComponent.m[/COLOR]
[COLOR="Blue"]/usr/bin/gcc  -arch x86_64 -isysroot /Developer/SDKs/MacOSX10.5.sdk -bundle -o libQTMovieViewComponent.jnilib *.o -framework JavaVM -framework Cocoa -framework QTkit [/COLOR]
Undefined symbols:
  "_objc_msgSendSuper2", referenced from:
      -[QTMovieController init] in QTMovieController.o
      -[QTMovieViewComponent mouseDown:] in QTMovieViewComponent.o
      -[QTMovieViewComponent mouseDragged:] in QTMovieViewComponent.o
      -[QTMovieViewComponent scrollWheel:] in QTMovieViewComponent.o
      -[QTMovieViewComponent init] in QTMovieViewComponent.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [jnipart] Error 1

Click to expand...

The command hilited in red performs compilation. The line hilited in blue performs linking.

Both commands are missing the option that tells the compiler and linker to produce 10.5-compatible code. The compiler generates code, so it needs more than just an SDK -- it needs to be told what language and runtime capabilities it can use.

This is the -mmacosx-version-min option to gcc, and it needs to be set to the value 10.5. Since it's not, the compiler targets the current OS, which is 10.6.

The Xcode name for this build setting is "Mac OS X deployment target". The gcc option is already noted.