Don't use malloc.h header on OpenBSD.

--- src/librcps.c.orig	Thu Nov 20 01:45:02 2014
+++ src/librcps.c	Thu Nov 20 01:45:17 2014
@@ -1,4 +1,3 @@
-#include <malloc.h>
 #include <string.h>
 #include <stdlib.h>
 #include <time.h>
