Add .clang-format CI check

.github/workflows/formatting.yml

@@ -0,0 +1,20 @@
+# Copyright 2024 The Khronos Group Inc.
+# Copyright 2024 RasterGrid Kft.
+# SPDX-License-Identifier: Apache-2.0
+name: Formatting
+
+on:
+  workflow_call:
+
+permissions:
+  contents: read
+
+jobs:
+  clang-format:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Run clang-format
+      uses: jidicula/[email protected]
+      with:
+        clang-format-version: '17'

.github/workflows/windows.yml

@@ -25,7 +25,11 @@ on:
   workflow_dispatch:
 
 jobs:
+  formatting:
+    uses: ./.github/workflows/formatting.yml
   windows:
+    # Shortcircuit and don't burn CI time when formatting will reject
+    needs: formatting
     strategy:
       matrix:
         os: [ windows-latest ]