What's this?
-arch ppc -arch i386
Mac universal build.
From gcc man page:
-arch arch
Compile for the specified target architecture arch. The allowable
values are i386, ppc and ppc64. Multiple options work, and direct
the compiler to produce ``universal'' binaries including object
code for each architecture specified with -arch. This option only
works if assembler and libraries are available for each architec-
ture specified. (APPLE ONLY)
Other things related to universal binary are:
-isysroot /Developer/SDKs/MacOSX...
needed on PPC, on Intel the system libraries are already universal.
This is not documented in the gcc man page, but I think is "similar" to -isystem.
But it works for all system headers and libraries/frameworks and accept a dir that contains all system hierarchy (from /).
-isystem dir
Search dir for header files, after all directories specified by -I
but before the standard system directories. Mark it as a system
directory, so that it gets the same special treatment as is applied
to the standard system directories.
--disable-dependency-tracking option to configure:
it doesn't use gcc's built-in dependency generation code, which does not work with multiple -arch targets.