String constants are now (const char *)s and must be explicitly cast to (char *).
operator new is expected to be empty or throw an expection instead of returning null. (ifdef'd for gcc 2.95+)
Stricter checks on register clobbering in embedded asm. (at least I think that's what it is)
Expects the main function to return int, not something similiar to it like PRInt32.
Still requires a tweak to remove -mno-486 from NSPR's *.mk files.