Use GitHub Actions (#407)

Author: RobLoach

.github/workflows/build.yml

@@ -0,0 +1,26 @@
+name: Build
+on: [push, pull_request]
+
+jobs:
+  linux:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: recursive
+        fetch-depth: 0
+
+    - name: Install
+      run: |
+        sudo apt-get update
+        sudo apt-get install cmake time g++-7 gcc-7 binutils libc6 python
+
+    - name: Configure
+      run: ./configure
+
+    - name: Build
+      run: make
+
+    - name: Test
+      run: make test