safe_set treat ':' and '#' differently

Treat '#' as a comment anywhere,
but ':' only at start of line.

libexec/rc/safe_eval.sh

@@ -1,6 +1,6 @@
 :
 # RCSid:
-#	$Id: safe_eval.sh,v 1.27 2026/04/22 16:11:57 sjg Exp $
+#	$Id: safe_eval.sh,v 1.28 2026/04/22 16:36:32 sjg Exp $
 #
 #	@(#) Copyright (c) 2023-2026 Simon J. Gerraty
 #
@@ -32,7 +32,7 @@ fi
 # "xtras" should be used with caution and cannot include ';'
 # 
 safe_set() {
-    ${SED:-sed} 's/^[ 	]*//;s/^[:#].*//;/^[A-Za-z_][A-Za-z0-9_]*=/!d;s;[^A-Za-z0-9_. 	"'"$1"'$,/=:+-];_;g'
+    ${SED:-sed} 's/^[ 	]*//;s/[ 	]*#.*//;s/^:.*//;/^[A-Za-z_][A-Za-z0-9_]*=/!d;s;[^A-Za-z0-9_. 	"'"$1"'$,/=:+-];_;g'
 }
 
 ##