stdlib: use shorhand wur for realloc prototype

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

include/stdlib.h

@@ -503,7 +503,7 @@ __BEGIN_NAMESPACE_STD
    the same pointer that was passed to it, aliasing needs to be allowed
    between objects pointed by the old and new pointers.  */
 extern void *realloc (void *__ptr, size_t __size)
-     __THROW __attribute_warn_unused_result__;
+     __THROW __wur;
 /* Free a block allocated by `malloc', `realloc' or `calloc'.  */
 extern void free (void *__ptr) __THROW;
 __END_NAMESPACE_STD