ci: Use improved version of install-meson-project

Copied from
  https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/main/.gitlab-ci/install-meson-project.sh

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3016>

.gitlab-ci/install-meson-project.sh

@@ -2,38 +2,81 @@
 
 set -e
 
-if [[ $# -lt 3 ]]; then
+usage() {
-  echo Usage: $0 [options] [repo-url] [commit] [subdir]
+  cat <<-EOF
-  echo  Options:
+	Usage: $(basename $0) [OPTION…] REPO_URL COMMIT
-  echo    -Dkey=val
+
+	Check out and install a meson project
+
+	Options:
+	  -Dkey=val      Option to pass on to meson
+	  --subdir       Build subdirectory instead of whole project
+	  --prepare      Script to run before build
+
+	  -h, --help     Display this help
+
+	EOF
+}
+
+TEMP=$(getopt \
+  --name=$(basename $0) \
+  --options='D:h' \
+  --longoptions='subdir:' \
+  --longoptions='prepare:' \
+  --longoptions='help' \
+  -- "$@")
+
+eval set -- "$TEMP"
+unset TEMP
+
+MESON_OPTIONS=()
+SUBDIR=.
+PREPARE=:
+
+while true; do
+  case "$1" in
+    -D)
+      MESON_OPTIONS+=( -D$2 )
+      shift 2
+    ;;
+
+    --subdir)
+      SUBDIR=$2
+      shift 2
+    ;;
+
+    --prepare)
+      PREPARE=$2
+      shift 2
+    ;;
+
+    -h|--help)
+      usage
+      exit 0
+    ;;
+
+    --)
+      shift
+      break
+    ;;
+  esac
+done
+
+if [[ $# -lt 2 ]]; then
+  usage
   exit 1
 fi
 
-MESON_OPTIONS=()
-
-while [[ $1 =~ ^-D ]]; do
-  MESON_OPTIONS+=( "$1" )
-  shift
-done
-
 REPO_URL="$1"
-TAG_OR_BRANCH="$2"
+COMMIT="$2"
-SUBDIR="$3"
-COMMIT="$4"
 
-REPO_DIR="$(basename ${REPO_URL%.git})"
+CHECKOUT_DIR=$(mktemp --directory)
+trap "rm -rf $CHECKOUT_DIR" EXIT
 
-git clone --depth 1 "$REPO_URL" -b "$TAG_OR_BRANCH"
+git clone --depth 1 "$REPO_URL" -b "$COMMIT" "$CHECKOUT_DIR"
-pushd "$REPO_DIR"
-pushd "$SUBDIR"
 
-if [ ! -z "$COMMIT" ]; then
+pushd "$CHECKOUT_DIR/$SUBDIR"
-  git fetch origin "$COMMIT"
+sh -c "$PREPARE"
-  git checkout "$COMMIT"
+meson setup --prefix=/usr _build "${MESON_OPTIONS[@]}"
-fi
-
-meson --prefix=/usr _build "${MESON_OPTIONS[@]}"
 meson install -C _build
 popd
-popd
-rm -rf "$REPO_DIR"