mjit.c: prefer $TMPDIR and $TMP
$TMPDIR
$TMP
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62492 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
mjit.c: prefer $TMPDIR and $TMP
$TMPDIRand$TMPover systemdefulat temporary directory, if exists, writable, and safe.
[ruby-core:85651] [Bug #14496]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62492 b2dd03c8-39d4-4d8f-98ff-823fe69b080e