Mixing MinGW and MSVC object files is indeed a problem as neither toolchain understands the other's debugging information. If you can get away with it, just do

Mixing MinGW and MSVC object files is indeed a problem as neither toolchain understands the other's debugging information. If you can get away with it, just don't support MSVC. If that's not an option, your best bet is probably restricting yourself to the common subset of C and C++...