msys2 & W10, Makefile doesn't support OS

I’m running into the “This makefile does not support your operating system.” on Windows 10, but my use-case is non-standard. Existing topics haven’t been much help.

I’m including the OF release inside the project folder instead of vice-versa. I’ve got the project running on both QT Creator and Xcode on OS X. I’m at a loss for what mingw32 on Win10 doesn’t like about this particular OF folder.

Building and running examples from an independent OF 0.9.3 msys2 release works fine, so I know the compiler itself is working.