Add basic GitHub Action

compile.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+
+set -euo pipefail
+
+files="$1"
+compiler="$2"
+options="$3"
+
+for f in $files; do
+  if [-f "$f" ]; then
+      echo "Compiling '$f'.."
+      $compiler $options $f
+      $compiler $options $f # Run twice to make sure everything is OK
+  else
+    echo "'$f' not found!"
+  fi
+done