diff --git a/chicken.h b/chicken.h
index bbcf420..a7c7289 100644
--- a/chicken.h
+++ b/chicken.h
@@ -154,7 +154,7 @@
 #ifdef HAVE_ALLOCA_H
 # include <alloca.h>
 #elif !defined(alloca) /* predefined by HP cc +Olibcalls */
-   char *alloca ();
+   void *alloca ();
 #endif