winpthreads: De-duplicate `struct timespec` by including <time.h>

Reference: https://sourceforge.net/p/mingw-w64/mailman/mingw-w64-public/thread/2d855f61-fd8e-9ccc-d110-934f58974906%40reactos.org/#msg37216256
Signed-off-by: Liu Hao <lh_mouse@126.com>
1 file changed