turn on rest of warnings flags on gnu compiler.
fix link order.
for example:
C:/MinGW/lib/libSDLmain.a;mingw32;C:/MinGW/bin/SDL.dll;C:/MinGW/lib/SDL_ttf.lib
->
mingw32;C:/MinGW/bin/SDL.dll;C:/MinGW/lib/libSDLmain.a;C:/MinGW/lib/SDL_ttf.lib