patch gcc 4.7.3 so the unwind code can make use of dl_iterate_phdr

we also need to remove --with-newlib, as that sets inhibit_libc
to true everywhere.

"--with-newlib:
Since a working C library is not yet available, this ensures that
the inhibit_libc constant is defined when building libgcc.
This prevents the compiling of any code that requires libc support."