diff --git a/src/proto/screen.pro b/src/proto/screen.pro
index 6831d42..b5b6eec 100644
--- a/src/proto/screen.pro
+++ b/src/proto/screen.pro
@@ -29,6 +29,7 @@
 void check_for_delay __ARGS((int check_msg_scroll));
 int screen_valid __ARGS((int clear));
 void screenalloc __ARGS((int clear));
+void free_screenlines __ARGS((void));
 void screenclear __ARGS((void));
 int can_clear __ARGS((char_u *p));
 void screen_start __ARGS((void));