Depend on OS_ID for platform detection
Depend on OS_ID for platform detection

Because we already depend on it, and it works better for
cross-compiling: testing for host-system instead of build-system

kealist/ren-c,codebybrett/ren-c,draegtun/ren-c,codebybrett/ren-c,hostilefork/rebol,rgchris/ren-c,kealist/ren-c,draegtun/ren-c,kealist/ren-c,rgchris/ren-c,rgchris/ren-c,giuliolunati/ren-c,codebybrett/ren-c,giuliolunati/ren-c,giuliolunati/ren-c,draegtun/ren-c,giuliolunati/ren-c,hostilefork/rebol,codebybrett/ren-c,draegtun/ren-c,codebybrett/ren-c,hostilefork/rebol,rgchris/ren-c,draegtun/ren-c,kealist/ren-c,draegtun/ren-c,hostilefork/rebol,hostilefork/rebol,kealist/ren-c,hostilefork/rebol,codebybrett/ren-c,giuliolunati/ren-c,rgchris/ren-c,kealist/ren-c