diff --git a/src/proto/gui_xmdlg.pro b/src/proto/gui_xmdlg.pro
index 4f88c2f..256fad7 100644
--- a/src/proto/gui_xmdlg.pro
+++ b/src/proto/gui_xmdlg.pro
@@ -1,3 +1,3 @@
 /* gui_xmdlg.c */
-char_u *gui_xm_select_font __ARGS((char_u *current));
+char_u *gui_xm_select_font(char_u *current);
 /* vim: set ft=c : */