[PATCH v5 13/13] CI: gate macos build jobs with MACOS_JOBS variable

The macos runners have limited availability (they aren't enabled for all
repositories, and have a monthly usage limit). Do not schedule macos
build jobs unless explicitly enabled with MACOS_JOBS=true variable.
Note: just setting the variable is not enough to have macos builds,
relevant runners need to be enabled too. Unfortunately there isn't any
built-in variable signaling runners availability.

Signed-off-by: Marek Marczykowski-Górecki <[email protected]>
---
New in v5

MACOS_JOBS=true wants to be set as a group variable in
xen-project/hardware group. Specifically, on this page:
https://gitlab.com/groups/xen-project/hardware/-/settings/ci_cd#ci-variables
---
 automation/gitlab-ci/build.yaml | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/automation/gitlab-ci/build.yaml b/automation/gitlab-ci/build.yaml
index 27eefec5f9a5..85831f44838b 100644
--- a/automation/gitlab-ci/build.yaml
+++ b/automation/gitlab-ci/build.yaml
@@ -13,7 +13,7 @@
       - '*/*.log'
     when: always
   needs: []
-  rules:
+  rules: &build-rules
     - if: $BUILD_FOR_TESTS_ONLY
       when: never
     - if: $CI_JOB_NAME =~ $SELECTED_JOBS_ONLY
@@ -806,6 +806,10 @@ debian-13-riscv64-gcc-randconfig:
 # macOS build jobs
 .macos-26:
   <<: *build
+  rules:
+    - if: $MACOS_JOBS != true
+      when: never
+    - *build-rules
   tags:
     - saas-macos-medium-m1
   image: macos-26-xcode-26
-- 
git-series 0.9.1