[gtk/wip.win32.fixes] demos: Fix minesweeper demos on Windows

[Chun-wei Fan <fanchunwei src gnome org>]

commit 8f26dfb8db3d1caecb45a54106b73b2734f764cc
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Sep 7 16:28:48 2020 +0800

    demos: Fix minesweeper demos on Windows
    
    Make sure the callback functions in the .ui files are exported, so that
    those functions can be recognized at runtime so that things run
    properly.

 demos/gtk-demo/listview_minesweeper.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/demos/gtk-demo/listview_minesweeper.c b/demos/gtk-demo/listview_minesweeper.c
index e43eaceb0b..736c47bcc9 100644
--- a/demos/gtk-demo/listview_minesweeper.c
+++ b/demos/gtk-demo/listview_minesweeper.c
@@ -428,7 +428,7 @@ sweeper_game_reveal_cell (SweeperGame *self,
   sweeper_game_check_finished (self);
 }
 
-void
+G_MODULE_EXPORT void
 minesweeper_cell_clicked_cb (GtkGridView *gridview,
                              guint        pos,
                              SweeperGame *game)
@@ -436,7 +436,7 @@ minesweeper_cell_clicked_cb (GtkGridView *gridview,
   sweeper_game_reveal_cell (game, pos);
 }
 
-void
+G_MODULE_EXPORT void
 minesweeper_new_game_cb (GtkButton   *button,
                          SweeperGame *game)
 {