Add Clang and Ninja toolchain setup for Linux CI builds.

Author: gpx1000

.github/workflows/simple_engine_ci.yml

@@ -28,6 +28,22 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Install Clang + Ninja (Linux)
+        if: runner.os == 'Linux'
+        shell: bash
+        run: |
+          set -euo pipefail
+          sudo apt-get update
+          sudo apt-get install -y clang ninja-build
+
+      - name: Select Clang toolchain (Linux)
+        if: runner.os == 'Linux'
+        shell: bash
+        run: |
+          set -euo pipefail
+          echo "CC=clang" >> "$GITHUB_ENV"
+          echo "CXX=clang++" >> "$GITHUB_ENV"
+
       - name: Set up MSVC dev environment
         if: runner.os == 'Windows'
         uses: ilammy/msvc-dev-cmd@v1
@@ -166,6 +182,8 @@ jobs:
         run: >
           cmake -S . -B build -G Ninja
           -DCMAKE_BUILD_TYPE=Release
+          -DCMAKE_C_COMPILER=clang
+          -DCMAKE_CXX_COMPILER=clang++
 
       - name: Build
         run: cmake --build build --target SimpleEngine --parallel 4