sdl2.mk is a copy of existing autotools based configuration, modified to instead
use CMake, which appears to be the preferred method when building for Windows,
msys2 project also uses the CMake system.

These patches come from msys2:
	- 001-fix-cmake-target-relocation.patch
	- 003-fix-static-library-name.patch

	Origin: https://github.com/msys2/MINGW-packages/tree/master/mingw-w64-SDL2