xcode build and gcc for universal binary

xCode
General-->Cross-Develop Using Target SDK:
Max-OS x 10.5
Then you can use features available on 10.5

build -> Architectures ( from target file):
按住mouse，之後手動輸入i386, x86_64, ppc ppc64

build --> Mac OS X Deployment Target
Mac os X 10.4
This is the minimum OS version you want to support

gcc
use -arch i386 -arch ppc
ex:
the object file generated is test.o
file test.o:
test.o (for architecture ppc7400): Mach-O object ppc
test.o (for architecture i386): Mach-O object i386