diff -Naur ctags-5.8.orig/lregex.c ctags-5.8/lregex.c
--- ctags-5.8.orig/lregex.c	2007-09-10 04:36:48.000000000 +0200
+++ ctags-5.8/lregex.c	2014-04-14 21:09:17.716000000 +0200
@@ -408,7 +408,7 @@
 		const char* regexfile = parameter + 1;
 		FILE* const fp = fopen (regexfile, "r");
 		if (fp == NULL)
-			error (WARNING | PERROR, regexfile);
+			error (WARNING | PERROR, "%s", regexfile);
 		else
 		{
 			vString* const regex = vStringNew ();