Added missing include files prevents gcc to issue warnings.

Signed-off-by Peter Huewe <peterhuewe@gmx.de>

--- aalib-1.4.0/src/aalib.h
+++ aalib-1.4.0/src/aalib.h
@@ -23,6 +23,8 @@
 #ifndef __AALIB_INCLUDED__
 #define __AALIB_INCLUDED__
 #include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
 #ifdef __cplusplus
 extern "C" {
 #endif