Do not spill colour from the -o' option in gcc'

The `-o' rule for gcc was a bit too greedy, matching everything
until the *last* word boundary.

Simply match non-space chars instead.

conf.gcc

@@ -20,7 +20,7 @@ regexp=\-O\d
 colours=green
 .........
 # -o
-regexp=\-o\s.+\b
+regexp=\-o\s[^\s]+
 colours=yellow
 .........
 # warning and error won't work, unless you redirect also