[gtk/wip/otte/macos-werror: 5/6] CI: turn on -Werror for MacOS build

[Benjamin Otte <otte src gnome org>]

commit 0c06343a31b8513f76bac792c20416c6d6e81665
Author: Benjamin Otte <otte redhat com>
Date:   Wed Nov 3 23:35:03 2021 +0100

    CI: turn on -Werror for MacOS build
    
    The build is error-free and we want to keep it that way.
    
    We'd also like to make Timm do real work instead of having to fix clang
    warnings all the time and this build is a clang build.

 .gitlab-ci.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 00184e023d..77499dd9ee 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -172,7 +172,8 @@ macos:
     - export PATH=/Users/gitlabrunner/Library/Python/3.7/bin:$PATH
     - export MESON_FORCE_BACKTRACE=1
   script:
-    - meson -Dx11-backend=false
+    - meson ${COMMON_MESON_FLAGS}
+            -Dx11-backend=false
             -Dbroadway-backend=true
             -Dmacos-backend=true
             -Dmedia-gstreamer=disabled