replaced malloc.h with stdlib.h to quiet compiler
diff --git a/tree.c b/tree.c
index 2719074..dd20318 100644
--- a/tree.c
+++ b/tree.c
@@ -11,7 +11,7 @@
 #include "config.h"
 #include <stdio.h>
 #include <ctype.h>
-#include <malloc.h>
+#include <stdlib.h>
 #include <string.h> /* for memset() only ! */
 
 #ifdef HAVE_ZLIB_H