diff --git a/src/proto/os_win32.pro b/src/proto/os_win32.pro
index 9f8b969..7ea5388 100644
--- a/src/proto/os_win32.pro
+++ b/src/proto/os_win32.pro
@@ -1,4 +1,5 @@
 /* os_win32.c */
+void mch_get_exe_name(void);
 HINSTANCE vimLoadLib(const char *name);
 int mch_is_gui_executable(void);
 HINSTANCE find_imported_module_by_funcname(HINSTANCE hInst, const char *funcname);