Fix WAIT polling interval on POSIX platforms
Fix WAIT polling interval on POSIX platforms

WAIT with a timeout internally encodes the timeout in milliseconds. The
actual POSIX host implementation however inadvertently uses this value
as a timeout in microseconds. This leads to a de-facto busy loop when
WAITing, as the internal timeouts are simply too short.

Originally discovered by Richard Smolak. Independently reported by
Bohdan Lechnowsky.

draegtun/ren-c,codebybrett/ren-c,earl/r3,mbk/ren-c,kealist/ren-c,rebol/rebol,codebybrett/ren-c,rebolsource/r3,rgchris/ren-c,rgchris/ren-c,mbk/ren-c,mbk/ren-c,codebybrett/ren-c,giuliolunati/ren-c,rebol/rebol,kealist/ren-c,hostilefork/rebol,rebol/rebol,rebolsource/r3,draegtun/ren-c,hostilefork/rebol,codebybrett/ren-c,codebybrett/ren-c,hostilefork/rebol,kealist/ren-c,earl/r3,giuliolunati/ren-c,rgchris/ren-c,draegtun/ren-c,draegtun/ren-c,rgchris/ren-c,kealist/ren-c,rgchris/ren-c,kealist/ren-c,giuliolunati/ren-c,giuliolunati/ren-c,hostilefork/rebol,hostilefork/rebol,earl/r3,rebolsource/r3,draegtun/ren-c,codebybrett/ren-c,mbk/ren-c,giuliolunati/ren-c,earl/r3,draegtun/ren-c,kealist/ren-c,hostilefork/rebol,rebol/rebol