Hello, Everyone

generic *is* a valid value for mtune; however, it's was added to gcc
relatively recently. This is only a rough guess, but the most likely
issue is that llvm-gcc is somehow picking up version of gcc bundled
with mingw from the path.

Yes, looks like this. And I suppose it can be due to famous access() breakage on Vista
preventing gcc driver from finding cc1 and friends in correct directories. I don't know the status
of this problem concerning llvm-gcc.