attempt some CI building using github actions

.github/workflows/ci-linux.yml

@@ -0,0 +1,17 @@
+name: CI (Linux)
+on: [push, pull_request]
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+    - name: Install dependencies
+      run: |
+        sudo apt-get update -qq
+        sudo apt-get install -y libsdl1.2-dev libasound2-dev libpng-dev libz-dev
+    - name: configure
+      run: DUMP_CONFIG_LOG=1 ./configure
+    - name: make
+      run: make