Add a coverity scan

.gitlab-ci.yml

@@ -30,6 +30,29 @@ stages:
     paths:
       - build/install/
 
+Coverity:
+  extends: .Debian
+  only:
+    - schedules
+  before_script:
+    - CI/install_debian_deps.sh gcc openmw-deps openmw-deps-dynamic
+    - curl -o /tmp/cov-analysis-linux64.tgz https://scan.coverity.com/download/linux64 --form project=$COVERITY_SCAN_PROJECT_NAME --form token=$COVERITY_SCAN_TOKEN
+    - tar xfz /tmp/cov-analysis-linux64.tgz
+  script:
+    - CI/before_script.linux.sh
+    - cd build
+    - cov-analysis-linux64-*/bin/cov-build --dir cov-int cmake --build . -- -j $(nproc)
+  after_script:
+    - tar cfz cov-int.tar.gz cov-int
+    - curl https://scan.coverity.com/builds?project=$COVERITY_SCAN_PROJECT_NAME \
+      --form token=$COVERITY_SCAN_TOKEN --form email=$GITLAB_USER_EMAIL \
+      --form file=@cov-int.tar.gz --form version="`git describe --tags`" \
+      --form description="`git describe --tags` / $CI_COMMIT_TITLE / $CI_COMMIT_REF_NAME:$CI_PIPELINE_ID  
+  variables:
+    CC: gcc
+    CXX: g++
+  timeout: 2h
+
 Debian_GCC:
   extends: .Debian
   cache: