What's new:
-----------

- Support for CLOCK_REALTIME_COARSE, CLOCK_MONOTONIC_COARSE,
  CLOCK_MONOTONIC_RAW, CLOCK_BOOTTIME clocks.


What changed:
-------------

- clock_nanosleep, pthread_condattr_setclock and timer_create now support
  all clocks, except CLOCK_PROCESS_CPUTIME_ID and CLOCK_THREAD_CPUTIME_ID.

- clock_setres is a no-op now.


Bug Fixes
---------

- Fix a thread race when initializing CLOCK_MONOTONIC.
  Addresses: https://cygwin.com/ml/cygwin/2018-11/msg00017.html

- Fix early timeout from pthread_cond_timedwait.
  Addresses: https://cygwin.com/ml/cygwin/2018-11/msg00171.html