[CMake] OSX universal binary support

[Bill Hoffman]

Mike Jackson wrote:
> There is and there is not.
> 
> What you need to try is putting -arch ppc -arch i386 for both the 
> CXX_FLAGS and C_FLAGS using ccmake.
> 
> That works for me in 10.4.11 with gcc.
> 

Actually, there is full support for universal binaries in CMake.
If you set this cmake cache variable:
   CMAKE_OSX_ARCHITECTURES=ppc;i386

Or set the same name environment variable before running CMake, the 
makefiles or Xcode will produce OSX universal binaries.

-Bill