squash! ci : add ccache to build-wasm

Attempt to fix ccaching.

Author: danbev

.github/workflows/build-wasm.yml

@@ -53,8 +53,10 @@ jobs:
           save: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
 
       - name: Build
+        env:
+          CCACHE_SLOPPINESS: time_macros
         run: |
-          emcmake cmake . -DCMAKE_BUILD_TYPE=${{ matrix.build }} \
+          emcmake cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build }} \
             -DCMAKE_C_COMPILER_LAUNCHER=ccache \
             -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
-          make
+          cmake --build build -j $(nproc)