winpthreads: Increase precision of CLOCK_REALTIME, add CLOCK_REALTIME_COARSE.

Use GetSystemTimePreciseAsFileTime() for CLOCK_REALTIME if available.
Always use GetSystemTimeAsFileTime() for CLOCK_REALTIME_COARSE.

Signed-off-by: Christian Franke <christian.franke@t-online.de>
Signed-off-by: Liu Hao <lh_mouse@126.com>
2 files changed