diff --git a/mozilla/jpeg/jconfig.h b/mozilla/jpeg/jconfig.h
index 4ea5fc7b648..289f956cdeb 100644
--- a/mozilla/jpeg/jconfig.h
+++ b/mozilla/jpeg/jconfig.h
@@ -30,8 +30,12 @@
 #define HAVE_UNSIGNED_SHORT 
 /* #define void char */
 /* #define const */
+#ifndef HAVE_STDDEF_H 
 #define HAVE_STDDEF_H 
+#endif /* HAVE_STDDEF_H */
+#ifndef HAVE_STDLIB_H
 #define HAVE_STDLIB_H 
+#endif /* HAVE_STDLIB_H */
 #undef NEED_BSD_STRINGS
 #undef NEED_SYS_TYPES_H
 #undef NEED_FAR_POINTERS