CI: add ASAN, MSAN, TSAN and UBSAN Sanitizers

AddressSanitizer (or ASan) is a programming tool that detects memory
corruption bugs such as buffer overflows or use after free. AddressSanitizer
is based on compiler instrumentation.

MemorySanitizer (MSan) is a detector of uninitialized memory reads in C/C++ programs.
Uninitialized values occur when stack- or heap-allocated memory is read before
it is written.

ThreadSanitizer is a tool that detects data races.

UndefinedBehaviorSanitizer (UBSan) is a fast undefined behavior detector. UBSan
catches various kinds of undefined behavior, for example:
- Using misaligned or null pointer
- Signed integer overflow
- Conversion to, from, or between floating-point types which would overflow the
  destination

The llvm.org states that Sanitizers have found thousands of bugs everywhere.
Sanitizers running during CI can prevent bugs from taking up residence. They
are helper tools to maintain bugs out.

1 files changed, 32 insertions, 0 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5eec8941..ce3663bb 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,6 +2,7 @@ image: registry.gitlab.gnome.org/gnome/gnome-settings-daemon:fedora.dev
 stages:
   - build
   - test
+  - manual
 
 .Log files: &log_files  [./*.log, _build/meson-logs/]
 
@@ -80,3 +81,34 @@ test:
         echo "== Testing =="
         meson test -C _build --verbose --no-stdsplit
       fi
+
+# Runs the sanitizers [address, thread, undefined, and memory].
+.sanitizer: &sanitizer
+  <<: *save_build_logs
+  stage: manual
+  when: manual
+  script:
+    - *environment_information
+    - *build_procedure
+    - *run_tests
+
+asan:
+  <<: *sanitizer
+  variables:
+    BUILD_OPTS: "-Db_sanitize=address"
+
+tsan:
+  <<: *sanitizer
+  variables:
+    BUILD_OPTS: "-Db_sanitize=thread"
+
+ubsan:
+  <<: *sanitizer
+  variables:
+    BUILD_OPTS: "-Db_sanitize=undefined"
+
+msan:
+  <<: *sanitizer
+  variables:
+    BUILD_OPTS: "-Db_sanitize=memory"
+    CC: "clang"