Fix the build with gtkmm 4:

https://github.com/transmission/transmission/issues/6392

Patch copied from upstream source repository:

https://github.com/transmission/transmission/commit/e116672b27b314d54514c96b1fa7aef1dee900b1

From e116672b27b314d54514c96b1fa7aef1dee900b1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C5=93ur?= <coeur@gmx.fr>
Date: Sun, 17 Dec 2023 16:37:35 +0100
Subject: [PATCH] fix: build error on  GTKMM-4 (#6393)

---
 gtk/OptionsDialog.cc | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/gtk/OptionsDialog.cc b/gtk/OptionsDialog.cc
index 08198540c10..8c28fc76f98 100644
--- a/gtk/OptionsDialog.cc
+++ b/gtk/OptionsDialog.cc
@@ -338,7 +338,16 @@ void TorrentFileChooserDialog::onOpenDialogResponse(int response, Glib::RefPtr<S
         bool const do_prompt = get_choice(std::string(ShowOptionsDialogChoice)) == "true";
         bool const do_notify = false;
 
-        auto const files = IF_GTKMM4(get_files2, get_files)();
+#if GTKMM_CHECK_VERSION(4, 0, 0)
+        auto files = std::vector<Glib::RefPtr<Gio::File>>();
+        auto files_model = get_files();
+        for (auto i = guint{ 0 }; i < files_model->get_n_items(); ++i)
+        {
+            files.push_back(gtr_ptr_dynamic_cast<Gio::File>(files_model->get_object(i)));
+        }
+#else
+        auto const files = get_files();
+#endif
         g_assert(!files.empty());
 
         /* remember this folder the next time we use this dialog */
cookbook.de.po?id=fbff88da7f6178a11ccd5f08c0c0927480255f2d'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/po/doc/guix-cookbook.de.po'>
<input type='hidden' name='id' value='fbff88da7f6178a11ccd5f08c0c0927480255f2d'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
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<tr><td><span title='2024-06-03 00:27:12 +0200'>2024-06-03</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=834a4195241806784d4b321b95f06d85f458ce18'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2024-05-01 02:42:54 +0200'>2024-05-01</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=8bf41c80ef13ea57e834f4e23d649bd99a3e08fc'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2024-04-01 14:09:20 +0200'>2024-04-01</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=fa98837b1d9586b9ca7bf77dae22c3bde0fc59b5'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2024-02-29 22:57:09 +0100'>2024-02-29</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=956f44b931f050fbffca51737000b9049808b3ca'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2024-02-01 18:34:22 +0100'>2024-02-01</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=6f78803b01d416ab421ba860751b764b9e4f33db'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2024-01-01 00:45:47 +0100'>2024-01-01</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=86b5fa100992527c434616482ba9cfd92b636d12'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-10-31 23:01:37 +0100'>2023-10-31</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=938a47c86d7bea785f33f42834c5c1f3dfa594b0'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-08-31 21:36:03 +0200'>2023-08-31</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=57ab9536db20f98a36aeb25972137fbd752686cc'>nls: Update translations.</a></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-06-30 14:26:07 +0200'>2023-06-30</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=8af22b493199a17f46351c2f3d9f6ee759e48564'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-05-31 17:23:21 +0200'>2023-05-31</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=8e9e6a6482f3ba98d1cdcad344ee488e8751fee7'>nls: Update translations.</a><span class='msg-avail'>...</span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-03-07 21:14:57 +0100'>2023-03-07</span></td><td><a href='/guix/commit/po/doc/guix-cookbook.de.po?id=d333958763b0840c4cd895601b079b68358a6a46'>nls: Update translations.</a></td><td>Julien Lepiller</td></tr>