only unset CI in mac

.gitlab-ci.yml

@@ -7,7 +7,6 @@ stages:
 .build_template:
   stage: build
   script:
-    - unset CI
     - python3 build-locally.py $CONFIG
   artifacts:
     expire_in: 1 month
@@ -21,12 +20,16 @@ stages:
 
 .build_template_build_osx_64:
   extends: .build_template
+  before_script:
+    - unset CI
   tags:
     - macos
     - intel
 
 .build_template_osx_arm64:
   extends: .build_template
+  before_script:
+    - unset CI
   tags:
     - macos
     - arm