The pthread_cond_timedwait requires a timeout relative to the Epoch.
So don't use uv__hrtime to set the timeout because it is relative to an
arbitrary time in the past. Use gettimeofday instead.
PR-URL: https://github.com/libuv/libuv/pull/1711
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Jamie Davis <davisjam@vt.edu>