Add CI.

.github/workflows/ci.yaml

@@ -0,0 +1,10 @@
+name: Tests
+on: [push, pull_request]
+jobs:
+   build_and_test:
+      runs-on: ubuntu-latest
+      steps:
+         - name: Checkout
+           uses: actions/checkout@v2
+         - name: Build cbc-file
+           uses: ericonr/voidlinux-crypto-gh-action@master

ci/run.sh

@@ -0,0 +1,2 @@
+#!/bin/sh -x
+make all