As MYS2/MINGW32 have not defined macro __MINGW__ and __MINGW__ is defined only at
GSConfig.h.in, the definition may have not effects over all scope. So some local definition was added.
(iii) <winsock2.h> warning hack
Previously, this hack was not accepted because
GSConfig.h.in is used global scope.
However, the warnings are still remained.
(2) back :
(i) hack to build at MINGW64
(3) script :
(i) some redundant package was removed and typing error was corrected.
(ii) Windows build was set to cairo-backend and WinUXTheme as default.
I hope these hacks be useful for gnustep Windows user. Thanks.