die: constify format string arg

We only display this string, so there's no need for it to be writable.
Constify away!

Acked-by: David Gibson <David@gibson.dropbear.id.au>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

util.h

@@ -23,7 +23,7 @@
  *                                                                   USA
  */
 
-static inline void __attribute__((noreturn)) die(char * str, ...)
+static inline void __attribute__((noreturn)) die(const char *str, ...)
 {
 	va_list ap;