ci: add GitHub Actions

Change-Id: Idc715edf136550b088f89c19b581f5478b296653
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..e7188d2
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,57 @@
+name: CI
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  linux:
+    name: ${{ matrix.compiler }} on ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        compiler: [g++-8, g++-9, g++-10, g++-11,
+                   clang++-7, clang++-8, clang++-9, clang++-10, clang++-11, clang++-12]
+        os: [ubuntu-20.04]
+        include:
+          - compiler: g++-7
+            os: ubuntu-18.04
+          - compiler: clang++-5.0
+            os: ubuntu-18.04
+          - compiler: clang++-6.0
+            os: ubuntu-18.04
+    runs-on: ${{ matrix.os }}
+    env:
+      CXX: ${{ matrix.compiler }}
+      NODE_LABELS: Linux Ubuntu
+      WAF_JOBS: 2
+    steps:
+      - name: Install C++ compiler
+        run: |
+          sudo apt-get -qy install ${CXX/clang++/clang}
+          ${CXX} --version
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Build and test
+        run: ./.jenkins
+
+  macos:
+    name: Xcode ${{ matrix.xcode }} on ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        xcode: ['11.3', '11.7', '12.4']
+        os: [macos-10.15]
+    runs-on: ${{ matrix.os }}
+    env:
+      NODE_LABELS: OSX OSX-10.15
+      WAF_JOBS: 3
+    steps:
+      - name: Set up Xcode
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: ${{ matrix.xcode }}
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Build and test
+        run: ./.jenkins