[librsvg/librsvg-2.42] CI: add a distcheck stage that runs "make distcheck" to build a tarball

[Federico Mena Quintero <federico src gnome org>]

commit 3156661ce06fb8da7e300f84e33818284df707f7
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri May 4 14:53:34 2018 -0500

    CI: add a distcheck stage that runs "make distcheck" to build a tarball

 .gitlab-ci.yml | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f66e1021..81207509 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -24,6 +24,7 @@ variables:
 stages:
   - test
   - lint
+  - distcheck
   - cross_distro
   - rustc
 
@@ -135,6 +136,15 @@ clippy:
     - cargo clippy --all
   when: manual
 
+tarball:
+  image: $AMD64_FEDORA_LATEST
+  stage: distcheck
+  variables:
+    LIBRSVG_DEBUG: "yes"
+  script:
+    - make distcheck
+  <<: *stage_2
+
 # STAGE 2 CROSS DISTRO TESTS
 #######################################################################