ci: enable bullseye-backports

Part-of: <https://gitlab.freedesktop.org/monado/monado/-/merge_requests/2261>

.gitlab-ci.yml

@@ -132,7 +132,7 @@ win:container_prep:
 .monado.variables.debian:bullseye:
   variables:
     FDO_DISTRIBUTION_VERSION: "bullseye"
-    FDO_DISTRIBUTION_TAG: "2024-03-21"
+    FDO_DISTRIBUTION_TAG: "2024-06-26"
 
 # Variables for build and usage of Debian bookworm-ndk image
 .monado.variables.debian:bookworm-ndk:
@@ -188,6 +188,7 @@ debian:bullseye:container_prep:
 
   variables:
     FDO_DISTRIBUTION_PACKAGES: 'build-essential ca-certificates cmake curl debhelper devscripts dput-ng gettext-base git glslang-tools libbluetooth-dev libbsd-dev libcjson-dev libdbus-1-dev libegl1-mesa-dev libeigen3-dev libgl1-mesa-dev libglvnd-dev libgstreamer-plugins-base1.0-dev libgstreamer1.0-dev libhidapi-dev libopencv-dev libsdl2-dev libsystemd-dev libudev-dev libusb-1.0-0-dev libuvc-dev libv4l-dev libvulkan-dev libwayland-dev libx11-dev libx11-xcb-dev libxcb-randr0-dev libxrandr-dev libxxf86vm-dev ninja-build pandoc patch pkg-config python3 unzip wayland-protocols wget'
+    FDO_DISTRIBUTION_EXEC: 'env FDO_CI_CONCURRENT=${FDO_CI_CONCURRENT} bash .gitlab-ci/bullseye_backports.sh'
 
 # Make Debian bookworm-ndk image
 debian:bookworm-ndk:container_prep:

.gitlab-ci/bullseye_backports.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: 2024, Collabora, Ltd. and the Monado contributors
+
+set -e
+
+(
+	echo 'deb https://deb.debian.org/debian bullseye-backports main contrib' > /etc/apt/sources.list.d/backports.list
+	apt-get update && apt-get upgrade
+	apt-get install --no-install-recommends -y -t bullseye-backports cmake
+)

.gitlab-ci/config.yml

@@ -117,7 +117,8 @@ distributions:
               XRT_HAVE_OPENCV: "OFF"
 
       - codename: bullseye
-        tag: "2024-03-21"
+        tag: "2024-06-26"
+        script: bullseye_backports.sh
         deb_version_suffix: bpo11
         packages:
           <<: *default_debian_packages