Add Webassembly build job to CI workflow

Author: Scavanger

.github/workflows/ci.yml

@@ -266,6 +266,41 @@ jobs:
             ./build_SITL/*.exe
             ./build_SITL/cygwin1.dll
 
+    build-SITL-Webassembly:
+      runs-on: ubuntu-latest
+      steps:
+        - uses: actions/checkout@v4
+        - name: Install dependencies
+          run: sudo apt-get update && sudo apt-get -y install ninja-build
+        - name: Setup Emscripten
+          uses: pyodide/setup-emsdk@v15
+        - name: Setup environment
+          env:
+            ACTIONS_ALLOW_UNSECURE_COMMANDS: true
+          run: |
+            # This is the hash of the commit for the PR
+            # when the action is triggered by PR, empty otherwise
+            COMMIT_ID=${{ github.event.pull_request.head.sha }}
+            # This is the hash of the commit when triggered by push
+            # but the hash of refs/pull/<n>/merge, which is different
+            # from the hash of the latest commit in the PR, that's
+            # why we try github.event.pull_request.head.sha first
+            COMMIT_ID=${COMMIT_ID:-${{ github.sha }}}
+            BUILD_SUFFIX=ci-$(date '+%Y%m%d')-$(git rev-parse --short ${COMMIT_ID})
+            VERSION=$(grep project CMakeLists.txt|awk -F VERSION '{ gsub(/[ \t)]/, "", $2); print $2 }')
+            echo "BUILD_SUFFIX=${BUILD_SUFFIX}" >> $GITHUB_ENV
+            echo "BUILD_NAME=inav-${VERSION}-${BUILD_SUFFIX}" >> $GITHUB_ENV
+            echo "NUM_CORES=$(grep processor /proc/cpuinfo  | wc -l)" >> $GITHUB_ENV
+        - name: Build SITL
+          run: mkdir -p build_WASM && cd build_WASM && cmake -DWASM=ON -DWARNINGS_AS_ERRORS=ON -G Ninja .. && ninja -j${{ env.NUM_CORES }}
+        - name: Upload artifacts
+          uses: actions/upload-artifact@v4
+          with:
+            name: ${{ env.BUILD_NAME }}_WASM
+            path: | 
+              ./build_WASM/*_WASM.*
+              ./build_WASM/*.html
+
   test:
     #needs: [build]
     runs-on: ubuntu-latest