gitlab-ci: Add for gitlab.freedesktop.org

Looks quite a bit like the travis path, doesn't it? Still, nice to not
rely on an external service if we don't have to.

Signed-off-by: Adam Jackson <ajax@redhat.com>

.gitlab-ci.yml

@@ -0,0 +1,13 @@
+image: docker:latest
+services:
+    - docker:dind
+
+before_script:
+    - echo FROM nwnk/xserver-travis-rawhide:v5 > Dockerfile
+    - echo ADD . /root >> Dockerfile
+    - echo WORKDIR /root >> Dockerfile
+    - docker build -t withgit .
+
+job:
+    script:
+        - docker run --volume $HOME/.ccache:/root/.ccache withgit ./test/scripts/build-travis-deps.sh