[Linux] Fix the error handling
[Linux] Fix the error handling

"actual" is "unsigned" so comparing it with "< 0" will always be false

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