winpthreads: Separate MSVC and MinGW specific flags and targets

- don't pass -D__USE_MINGW_ANSI_STDIO=0 to MSVC;
- don't build libgcc/fakelib with MSVC.

Signed-off-by: Antonin Décimo <antonin@tarides.com>
Signed-off-by: Martin Storsjö <martin@martin.st>
1 file changed