Define AMD64 for 64-bit mingw.
mingw-w64 have isinf
Fix cast error.
mingw-w64 don't need hack for SecPkgContext_AccessToken
Use modern ICU libraries when link with system wide ICU.
mingw-w64 don't have win98 support.
Add missing sources for fbintl library
Fix using function pointer.
Fix redefinition of matherr.
Fix warnings about missing defines.