Fix #4: add Windows and Mac OS runners

.gitlab-ci.yml

@@ -16,8 +16,9 @@ stages:
   - execute
   - cleanup
 
-before_script:
-  - cp $SSH_PRIVATE_KEY id_rsa
+.with-rsa-key:
+  before_script:
+    - cp $SSH_PRIVATE_KEY id_rsa
 
 fmt:
   tags:
@@ -29,13 +30,17 @@ validate:
   tags:
     - linux
     - small
-  extends: .terraform:validate
+  extends:
+    - .terraform:validate
+    - .with-rsa-key
 
 build:
   tags:
     - linux
     - small
-  extends: .terraform:build
+  extends:
+    - .terraform:build
+    - .with-rsa-key
   environment:
     name: $TF_STATE_NAME
 
@@ -43,23 +48,64 @@ deploy:
   tags:
     - linux
     - small
-  extends: .terraform:deploy
+  extends:
+    - .terraform:deploy
+    - .with-rsa-key
   dependencies:
     - build
   rules:
-    - when: manual
 
-execute:
+execute linux:
   stage: execute
   image: alpine
   tags:
     - terraform
     - docker
   script:
-    - echo Greetings from runner!
+    - apk add gcc musl-dev
+    - gcc -o hello_world.linux hello_world.c
+  artifacts:
+    paths:
+      - hello_world.linux
+
+execute windows:
+  stage: execute
+  image: alpine
+  tags:
+    - terraform
+    - windows
+  script:
+    # The trick for running cmd scripts from powershell runner is documented
+    # here:
+    # https://gitlab.com/guided-explorations/microsoft/windows/call-cmd-from-powershell/-/blob/master/.gitlab-ci.yml
+    - |
+      set-content $env:public\inline.cmd -Value @'
+      call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
+      cl /Fe:hello_world.exe hello_world.c
+      '@
+      CMD.EXE /C $env:public\inline.cmd
+      exit $LASTEXITCODE
+  artifacts:
+    paths:
+      - hello_world.exe
+
+execute macos:
+  stage: execute
+  image: alpine
+  tags:
+    - terraform
+    - macos
+  script:
+    - clang -o hello_world.macos hello_world.c
+  artifacts:
+    paths:
+      - hello_world.macos
 
 destroy:
   tags:
     - linux
     - small
-  extends: .terraform:destroy
+  extends:
+    - .terraform:destroy
+    - .with-rsa-key
+