--- osdef.h.in.orig	2015-06-28 21:22:56 UTC
+++ osdef.h.in
@@ -111,7 +111,7 @@ extern int   setsid __P((void));
 extern int   setpgid __P((int, int));
 extern int   tcsetpgrp __P((int, int));
 #endif
-extern int   ioctl __P((int, int, char *));
+extern int   ioctl __P((int, unsigned long, ...));
 
 extern int   kill __P((int, int));