Use m_cast to cast away const modifier
Use m_cast to cast away const modifier

This is caught by a C++11 compiler

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