Tolerate STRING! for CFLAGS and LDFLAGS
Tolerate STRING! for CFLAGS and LDFLAGS

Attempt to work around build breakage caused by FFI as module, where
the CFLAGS and LDFLAGS are getting set to STRING!.

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