replaced malloc.h with stdlib.h to quiet compiler
diff --git a/tester.c b/tester.c
index 0075ad7..2efbcb7 100644
--- a/tester.c
+++ b/tester.c
@@ -24,7 +24,7 @@
 #endif
 #include <stdio.h>
 #include <string.h>
-#include <malloc.h>
+#include <stdlib.h>
 
 #include "parser.h"
 #include "tree.h"