[PATCH] thread.c: favor timespec internally
This results in fewer conversion on common modern systems with
support for clock_gettime, pthread_cond_timedwait and ppoll.
gettimeofday is declared obsolete by POSIX.1-2008, so it is yet
another reason to move away from it. This also appears to result
in the reduction of compatibility code required for dealing
with inconsistent implementations of "struct timeval".tv_sec
In the future, this will also result in fewer conversions for
kqueue and pselect if we elect to use them.
Will commit soonish