Comment checkdiff output on PRs

.github/workflows/checkdiff.yml

@@ -3,6 +3,8 @@ on: pull_request
 
 jobs:
   checkdiff:
+    permissions:
+      pull-requests: write
     runs-on: ubuntu-latest
     steps:
       - name: Set up repo
@@ -12,6 +14,17 @@ jobs:
           git remote add upstream "${{ github.event.pull_request.base.repo.clone_url }}"
           git fetch upstream
       - name: Checkdiff
+        id: checkdiff
         working-directory: rgbds
         run: |
-          make checkdiff "BASE_REF=${{ github.event.pull_request.base.sha }}" Q= | tee log
+          make checkdiff "BASE_REF=${{ github.event.pull_request.base.sha }}" | tee log
+      - name: Comment
+        uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: `**Checkdiff:** <pre><code>${{steps.checkdiff.outputs.response}}</code></pre>`
+            })