The inclusion of mingw-w64 fixes T5979.
This package contains libraries, runtimes and binaries for the
MinGW-w64 target, both 32 and 64 architectures.
I've also added empty headers in pkgfiles, otherwise It cannot
be built. Depends on mingw-w64-gcc.
Also It requires to be rebuilt for winpthreads inclusion.
Signed-off-by: Martin Reboredo <email@example.com>