https://bugs.gentoo.org/969468
https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/2610
https://gitlab.gnome.org/GNOME/gimp/-/commit/cae3be98df77b27ebaa6b9a07a5d64f375f18e28

From cae3be98df77b27ebaa6b9a07a5d64f375f18e28 Mon Sep 17 00:00:00 2001
From: Alfred Wingate <parona@protonmail.com>
Date: Sat, 31 Jan 2026 20:21:27 +0200
Subject: [PATCH] tools/gen-languages: query user locale before falling back to
 en_US

setlocale(LC_ALL, "") queries the user locale.

setlocale(LC_ALL, NULL) also queries the locale, but not the user
locale. It actually queries the programs locale, which by default is C.

Otherwise the user would need to have en_US.UTF-8 available no matter
what.

Check that derivates UTF8 of C locale aren't used as well.

Bug: https://bugs.gentoo.org/969468
Fixes: 88261f8b4cab65350cd858e9221a91da4c7f86db
Signed-off-by: Alfred Wingate <parona@protonmail.com>
--- a/tools/gen-languages.c
+++ b/tools/gen-languages.c
@@ -280,8 +280,8 @@ gimp_language_store_parser_init (GError **error)
       goto cleanup;
     }
 
-  locale = setlocale (LC_ALL, NULL);
-  if (g_strcmp0 (locale, "C") == 0 || g_strcmp0 (locale, "POSIX") == 0)
+  locale = setlocale (LC_ALL, "");
+  if (g_strcmp0 (locale, "C") == 0 || g_strcmp0 (locale, "POSIX") == 0 || g_str_has_prefix (locale, "C."))
     {
       /* Note: we do not care about what we set, except not C or POSIX.
        * It may be any valid locale. This needs to be set so that this
-- 
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