permit -DMALLOC_STATS to compile again

noticed by Jonathan Armani & Fabien Romano
ugh+ok otto@

src/lib/libc/stdlib/malloc.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: malloc.c,v 1.117 2009/10/20 21:19:37 pirofti Exp $	*/
+/*	$OpenBSD: malloc.c,v 1.118 2009/11/02 19:26:17 todd Exp $	*/
 /*
  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
  *
@@ -1371,7 +1371,7 @@ orealloc(void *p, size_t newsz)
 
 		if (rnewsz > roldsz) {
 			if (!mopts.malloc_guard) {
-				STATS_INC(g_pool.cheap_realloc_tries);
+				STATS_INC(g_pool->cheap_realloc_tries);
 				zapcacheregion(g_pool, p + roldsz);
 				q = MMAPA(p + roldsz, rnewsz - roldsz);
 				if (q == p + roldsz) {