Don't use malloc.h header on OpenBSD.

--- stocks/stocks.c.orig	Thu Nov 20 01:56:13 2014
+++ stocks/stocks.c	Thu Nov 20 01:56:21 2014
@@ -22,7 +22,6 @@
 
 #include <stdio.h>
 #include <string.h>
-#include <malloc.h>
 #include <stdlib.h>
 
 #ifdef __WINDOWS__
