Fix missing TCOD_WIN64 define on MinGW64
Note that __MINGW32__ and __MINGW64__ are both defined on MinGW64.
This code was messing up the size of intptr.
#elif defined( __MINGW32__ )
# define TCOD_WINDOWS
# define TCOD_MINGW32
-# define TCOD_WIN32
-#elif defined( __MINGW64__ )
-# define TCOD_WINDOWS
-# define TCOD_MINGW32
# ifdef _WIN64
# define TCOD_WIN64
# define TCOD_64BITS
