Add -fixmingwaw option to expand __MINGW_NAME_AW in macro bodies

The MinGW.org/MinGW-w64 headers have lots of cases like this:
	#ifdef UNICODE
		#define __MINGW_NAME_AW(s) s##W
	#else
		#define __MINGW_NAME_AW(s) s##A
	#endif
	#define FunctionName __MINGW_NAME_AW(FunctionName)
which redefines FunctionName to the *A or *W version as needed.

However, in FB such #defines cause "recursive #define" errors,
thus they need to be changed to
	#ifdef UNICODE
		#define FunctionName FunctionNameW
	#else
		#define FunctionName FunctionNameA
	#endif
fixmingwaw: Only expand the __MINGW_NAME_AW() call, nothing else
fixmingwaw: Also handle __MINGW_NAME_{AW_EXT,UAW,UAW_EXT}