(realloc): Handle NULL for first parameter correctly.

elf/dl-minimal.c

@@ -111,6 +111,8 @@ void * weak_function
 realloc (void *ptr, size_t n)
 {
   void *new;
+  if (ptr == NULL)
+    return malloc (n);
   assert (ptr == alloc_last_block);
   alloc_ptr = alloc_last_block;
   new = malloc (n);