Typo "WIN32" instead of "_WIN32"?
Hi there,

This code is checking if `WIN32` is defined, but shouldn't it be checking `_WIN32`?
https://github.com/Dav1dde/glad/blob/4014836cb06e86058b1e82b4b1777f511e31ef11/glad/lang/c/loader/__init__.py#L108
