Replace mingw/gnuwin32 packages to msys2
Add missing host option of x86_64 build
Add patch to MSYS2 based DevKit

The MSYS2 based patch utility embeds the manifest required to
prevent UAC issues on Windows systems.
Update mingw64-{32,64}-4.9.0 to rev2
Add mingw64-{32,64}-4.9.1 rev0 support