add clcache

.github/workflows/build.yml

@@ -190,17 +190,27 @@ jobs:
     name: Win64 package (native)
     runs-on: windows-latest
     steps:
+      - name: Fetch cache
+        uses: actions/cache@v3
+        with:
+          path: "%HOME%/clcache"
+          key: clcache-win64-${{ github.sha }}
+          restore-keys: |
+            clcache-win64
       - name: Clone DFHack
         uses: actions/checkout@v3
         with:
           submodules: true
           fetch-depth: 0
+      - name: Install dependencies
+        run: pip install clcache
+      - run: pip install 'sphinx<4.4.0'
       - name: Configure DFHack
         run: |
-          cmake -S . -B build -G "Visual Studio 17 2022" -DCMAKE_INSTALL_PREFIX=build/image
+          cmake -S . -B build -G "Visual Studio 17 2022" -DCMAKE_INSTALL_PREFIX=build/image -DCMAKE_C_COMPILER_LAUNCHER=clcache -DCMAKE_CXX_COMPILER_LAUNCHER=clcache -DBUILD_DOCS:BOOL=1 -DBUILD_STONESENSE:BOOL=1
       - name: Build DFHack
         run: |
-          cmake --build build --config Release --target install
+          cmake --build build -j 2 --config Release --target install
       - name: Format artifact name
         id: artifactname
         run: |