ci: Drop FreeBSD 12 CI runner as it’s EOL

It’s EOL and accordingly nobody wants to maintain the runner. We still
have the FreeBSD 13 runner to test against (on this branch and on
`main`).

See https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3740#note_1957840

Signed-off-by: Philip Withnall <pwithnall@gnome.org>

.gitlab-ci.yml

@@ -444,52 +444,6 @@ vs2017-x64-static:
     paths:
       - _build/meson-logs
 
-freebsd-12-x86_64:
-  # The FreeBSD 13 build is run on each commit, so the FreeBSD 12 build can be
-  # run less regularly to save CI resources. The chance of a regression on
-  # FreeBSD 12 and not FreeBSD 13 is tiny.
-  extends: .only-schedules
-  stage: build
-  tags:
-    # To run a FreeBSD builder, install gitlab-runner package and start both
-    # gitlab-runner and dbus service because we need /var/lib/dbus/machine-id.
-    # To compile GLib, you still have to install the following packages:
-    # desktop-file-utils gettext libiconv meson pkgconf python3 shared-mime-info
-    - freebsd-12
-  needs: []
-  variables:
-    # CPPFLAGS is required because libintl doesn't use pkg-config.
-    CPPFLAGS: -I/usr/local/include
-    # FIXME: Workaround meson inability to set LD_LIBRARY_PATH.
-    # https://github.com/mesonbuild/meson/issues/1383
-    # https://github.com/mesonbuild/meson/issues/1635
-    # https://github.com/mesonbuild/meson/issues/2881
-    LDFLAGS: -L/usr/local/lib -Wl,--disable-new-dtags
-    # FreeBSD supports C.UTF-8 locale since 12.1.
-    LANG: C.UTF-8
-  before_script:
-    - bash .gitlab-ci/show-execution-environment.sh
-  script:
-    # We cannot use -Wl,--no-undefined because GLib uses 'environ' variable.
-    # FreeBSD supports xattr, but its API is different from Linux xattr.
-    # FIXME: extattr(2) support: https://gitlab.gnome.org/GNOME/glib/issues/1404
-    # localstatedir is needed for access to /var/lib/dbus/machine-id
-    - meson setup ${MESON_COMMON_OPTIONS} --localstatedir=/var -Db_lundef=false -Dxattr=false _build
-    - meson compile -C _build
-    - bash -x ./.gitlab-ci/run-tests.sh
-  artifacts:
-    reports:
-      junit:
-        - _build/meson-logs/testlog.junit.xml
-        - _build/meson-logs/testlog-*.junit.xml
-    name: "glib-${CI_JOB_NAME}-${CI_COMMIT_REF_NAME}"
-    when: always
-    expire_in: 1 week
-    paths:
-      - "_build/config.h"
-      - "_build/glib/glibconfig.h"
-      - "_build/meson-logs"
-
 freebsd-13-x86_64:
   extends: .only-origin
   stage: build