using sys.maxsize isn't safe for cross builds. it should at least guarded by 'if not cross_compiling'.

I still think that the preferred way to get the library dirs is to ask the compiler (patch attached), however this will add "incompatible" library dirs as well, at least for multilib'd gcc builds, and leading to linker warnings when building the extensions. At least when using gcc this should address the issue finding the lib32 and libx32 dirs.