ci: Allow any path within gdb safe-load

In certain cases, the validate runner will try to get a stacktrace
from gdb, which will currently complain about loading the .gdbinit
file.

warning: File "/builds/gstreamer/gstreamer/.gdbinit" auto-loading
has been declined by your `auto-load safe-path' set to
"$debugdir:$datadir/auto-load".

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5769>

.gitlab-ci.yml

@@ -586,6 +586,11 @@ build macos:
     - changes:
         *modules_changes
   script:
+    # Disable gdb debugdir safeload
+    # The CI will execute any code submitted to it anyway
+    - mkdir -p ~/.config/gdb
+    - echo "set auto-load safe-path /" >> ~/.config/gdb/gdbinit
+
     - $CI_PROJECT_DIR/ci/scripts/build.sh
     - $CI_PROJECT_DIR/ci/scripts/test.sh
   after_script: