Replace the malloc.h header with stdlib.h.

--- stocks/lists.c.orig	Thu Nov 20 01:55:29 2014
+++ stocks/lists.c	Thu Nov 20 01:56:03 2014
@@ -20,7 +20,7 @@
 
 #define __LISTS_C__
 
-#include <malloc.h>
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
