can libtool do universal binary

[Perrog]

Hi!

Has anyone been using libtool for universal binary builds on Mach-O/Mac OS X? Are there any other platform that have similar requirements? In summary, an "universal build" is a Mach-O object or binary file format containing both PowerPC and Intel architectures, in an architecture independend file format. Basically, you run gcc two times and build it for ppc, then for i386. Lastly you use a magic tool, in this case "lipo", that  combines the two architectures into a single binary file.

Are there other platforms having parallells to universal builds? What would this really require from libtool? Or should universal builds be handled by other methods?

===== Example, showing the basic commands used. Build each architecture in own folders, then combine them into a single binary.

# Directory layout:

$ ll

drwxr-xr-x    6 perrog  perrog  204 May 11 11:26 ./

drwx------   17 perrog  perrog  578 May 11 10:50 ../

-rw-r--r--    1 perrog  perrog   73 May 11 10:53 foo.c

drwxr-xr-x    6 perrog  perrog  204 May 11 11:21 i386/

drwxr-xr-x    6 perrog  perrog  204 May 11 11:20 ppc/

drwxr-xr-x    3 perrog  perrog  102 May 11 11:26 universal/

(

  cd ppc # build Power PC architecture

  libtool --mode=compile gcc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch ppc -g -O -c ../foo.c

  libtool --mode=link gcc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch ppc -g -O -o libfoo.la foo.lo -version-info 1:1:0 -rpath /usr/local/lib

)

(

  cd i386 # Build Intel architecture

  libtool --mode=compile gcc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -g -O -c ../foo.c

  libtool --mode=link gcc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -g -O -o libfoo.la foo.lo -version-info 1:1:0 -rpath /usr/local/lib

)

# Inspecting architectures with file command

$ file i386/.libs/libfoo.1.0.1.dylib ppc/.libs/libfoo.1.0.1.dylib 

i386/.libs/libfoo.1.0.1.dylib: Mach-O dynamically linked shared library i386

ppc/.libs/libfoo.1.0.1.dylib:  Mach-O dynamically linked shared library ppc

(

  cd universal # Combine PowerPC and Intel architectures

  lipo -create ../i386/.libs/libfoo.1.0.1.dylib ../ppc/.libs/libfoo.1.0.1.dylib -output libfoo.1.0.1.dylib

)

# Inspecting architecture with file command

$ file universal/libfoo.1.0.1.dylib 

universal/libfoo.1.0.1.dylib: Mach-O universal binary with 2 architectures

universal/libfoo.1.0.1.dylib (for architecture i386):   Mach-O dynamically linked shared library i386

universal/libfoo.1.0.1.dylib (for architecture ppc):    Mach-O dynamically linked shared library ppc