By always instantiating extern inlines, the patch has discovered
2 assembly errors, which were fixed in the original mingw64 in 2009.
This fixes those errors.
Additionally it changes __CRT_INLINE in win32/include/_mingw.h
from `extern __inline__` to `static __inline__`.
__CRT_INLINE is used exclusively in header files and as such
it should not create externally visible instantiations like a `extern
inline` would (as per the C standard).
