should the question be "what's the first mingw gcc version that -mno-cygwin usage unnecessary" rather than finding the first version the option was removed?

and, does it matter whether you're building on win for win, or cross compiling for win from nix?

sadly, i don't know gcc internals but a post to the mingw and/or mingw-w64 ml's should get the right people weighing in.

btw, can distutils do a lightweight configure-like check for feature presence rather than going a gcc version check?