Index: uspace/lib/c/include/mem.h
===================================================================
--- uspace/lib/c/include/mem.h	(revision 2d1195c0dd1b314c846280e600e9899f43e9c478)
+++ uspace/lib/c/include/mem.h	(revision 26346bd55c100239a5c5aade700dd038b5a04f7b)
@@ -38,10 +38,10 @@
 #include <sys/types.h>
 
+#define memset(dst, val, cnt)  __builtin_memset((dst), (val), (cnt))
+#define memcpy(dst, src, cnt)  __builtin_memcpy((dst), (src), (cnt))
+
 #define bzero(ptr, len)  memset((ptr), 0, (len))
 
-extern void *memset(void *, int, size_t);
-extern void *memcpy(void *, const void *, size_t);
 extern void *memmove(void *, const void *, size_t);
-
 extern int bcmp(const void *, const void *, size_t);