feat: Add GitHub Actions workflow for cross-platform CI builds.

Author: ProgrammerKR

.github/workflows/benchmarks.yml

@@ -23,8 +23,21 @@ jobs:
       - name: Checkout source
         uses: actions/checkout@v4
 
-      - name: Setup CMake
-        uses: lukka/get-cmake@latest
+      - name: Install LLVM (Ubuntu)
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y llvm-dev libclang-dev clang
+
+      - name: Install LLVM (macOS)
+        if: matrix.os == 'macos-latest'
+        run: |
+          brew install llvm
+          echo "CMAKE_PREFIX_PATH=$(brew --prefix llvm)" >> $GITHUB_ENV
+
+      - name: Install LLVM (Windows)
+        if: matrix.os == 'windows-latest'
+        run: choco install llvm -y
 
       - name: Configure
         shell: bash