ci: Use sudo to run meson install

Meson stopped using polkit for automatic priviledge elevation, and
will no longer attempt any priviledge elevation when not running
interactively.

Running the entire install command as root used to be problematic
in the past, as it could result in ownership changes of files in
the build directory that would result in build failures later,
but the aforementioned change leaves us with little choice.

Presumably those issues have been fixed, let's hope that's true.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3173>

.gitlab-ci.yml

@@ -154,9 +154,6 @@ variables:
                       mutter mutter-devel \
                       gnome-shell
 
-      # Replace pkexec with sudo, to make meson use it if needed
-      ln -sfv /usr/bin/sudo /usr/bin/pkexec
-
       # Ensure that we mark the project clone dir as safe directory
       git config --system --add safe.directory "$CI_PROJECT_DIR"
 
@@ -349,7 +346,7 @@ check-code-style:
         $BASE_MESON_OPTIONS
         $EXTRA_MESON_OPTIONS
     - meson compile -C build
-    - meson install --dry-run -C build
+    - sudo meson install --dry-run -C build
   artifacts:
     expire_in: 1 day
     paths:
@@ -393,7 +390,7 @@ build-without-opengl-and-glx@x86_64:
         -Dwayland_eglstream=true
         -Dintrospection=false
     - meson compile -C build
-    - meson install --no-rebuild -C build
+    - sudo meson install --no-rebuild -C build
   artifacts:
     paths:
       - build/meson-logs
@@ -417,7 +414,7 @@ build-without-native-backend-and-wayland@x86_64:
         -Dnative_tests=false
         -Dintrospection=false
     - meson compile -C build
-    - meson install --no-rebuild -C build
+    - sudo meson install --no-rebuild -C build
   artifacts:
     paths:
       - build/meson-logs
@@ -439,7 +436,7 @@ build-wayland-only@x86_64:
         -Dnative_tests=false
         -Dintrospection=false
     - meson compile -C build
-    - meson install --no-rebuild -C build
+    - sudo meson install --no-rebuild -C build
   artifacts:
     paths:
       - build/meson-logs
@@ -578,11 +575,11 @@ can-build-gnome-shell@x86_64:
     - build-mutter@x86_64
   before_script:
     - !reference [.mutter.fedora@x86_64, before_script]
-    - meson install --no-rebuild -C build
+    - sudo meson install --no-rebuild -C build
   script:
     - .gitlab-ci/checkout-gnome-shell.sh
     - meson setup gnome-shell gnome-shell/build --prefix /usr -Dman=false
-    - meson install -C gnome-shell/build
+    - sudo meson install -C gnome-shell/build
 
 test-mutter-coverity:
   rules: