Add platform-specific int types for MingW32. After a patch from John Edwards.
Jan posted a different patch:
Most everyone (but MSVC) ships stdint types in either stdint.h or inttypes.h these days, but there
can be some tricky collisions with older installations, so I'd rather avoid a new portability
refinement tail this close to release.
git-svn-id: http://svn.xiph.org/trunk/ogg@5948 0101bb08-14d6-0310-b084-bc0e0c8e3800