diff --git a/src/proto/mouse.pro b/src/proto/mouse.pro
index 37a2f07..249e7f2 100644
--- a/src/proto/mouse.pro
+++ b/src/proto/mouse.pro
@@ -1,4 +1,6 @@
 /* mouse.c */
+void mouse_set_vert_scroll_step(long step);
+void mouse_set_hor_scroll_step(long step);
 int do_mouse(oparg_T *oap, int c, int dir, long count, int fixindent);
 void ins_mouse(int c);
 void ins_mousescroll(int dir);