[glib/wip/lantw/ci-Use-C.UTF-8-locale-on-FreeBSD-12] ci: Use C.UTF-8 locale on FreeBSD 12

[Ting-Wei Lan <lantw src gnome org>]

commit 8b3506bc813047c5bcc449ce8b76ca07e2d40a29
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Fri Sep 3 00:51:14 2021 +0800

    ci: Use C.UTF-8 locale on FreeBSD 12

 .gitlab-ci.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 73fbc1ba6..88a8548b6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -391,7 +391,8 @@ freebsd-12-x86_64:
   variables:
     CPPFLAGS: -I/usr/local/include
     LDFLAGS: -L/usr/local/lib -Wl,--disable-new-dtags
-    LANG: en_US.UTF-8
+    # FreeBSD supports C.UTF-8 locale since 12.1.
+    LANG: C.UTF-8
   before_script:
     - bash .gitlab-ci/show-execution-environment.sh
   script: