--- ./src/util/patcache.c.orig
+++ ./src/util/patcache.c
@@ -128,7 +128,7 @@
 /* add entry */
 void
 CacheFontPattern (FontPatternCachePtr cache,
-		  char *pattern,
+		  const char *pattern,
 		  int patlen,
 		  FontPtr pFont)
 {
@@ -174,7 +174,7 @@
 /* find matching entry */
 FontPtr
 FindCachedFontPattern (FontPatternCachePtr cache,
-		       char *pattern,
+		       const char *pattern,
 		       int patlen)
 {
     int				hash;