Am 31.07.2017 um 14:46 schrieb Jeff Mitchell:

Do I need different versions of mingw, installed side-by-side?

If you use MSYS2 there's no need to install any other dependencies. MSYS2 ships with mingw-w64 toolchains for both 32-bit and 64-bit builds (you don't need both if you only want to target one architecture).