Problem: mingw 64Bit relies on int[32/64]/uint[32/64] definitions
whereas mingw 32Bit does not.
Solution: include those defines in case of mingw 64Bit and exclude them
in case of mingw 32Bit.
Merge pull request #831 from sappo/master

Problem: mingw 64Bit relies on int[32/64]/uint[32/64] definitions whereas mingw 32Bit does not.