c-indent-new-comment-line: don't test for a macro in a comment

This fixes bug#9860.

* lisp/progmodes/cc-cmds (c-indent-new-comment-line): Test for
a comment/string before testing for a macro, thus preventing a
"macro" being spuriously recognized in a comment.  This allows
auto-fill-mode to work on a line beginning with # in a comment.

lisp/progmodes/cc-cmds.el

@@ -4909,7 +4909,8 @@ If a fill prefix is specified, it overrides all the above."
 	   (setq c-lit-limits (c-literal-limits nil nil t)))
 	 (unless c-lit-type
 	   (setq c-lit-type (c-literal-type c-lit-limits)))
-	 (if (memq (cond ((c-query-and-set-macro-start) 'cpp)
+	 (if (memq (cond ((memq c-lit-type '(c c++ string)) c-lit-type)
+			 ((c-query-and-set-macro-start) 'cpp)
 			 ((null c-lit-type) 'code)
 			 (t c-lit-type))
 		   c-ignore-auto-fill)