Detect Makefiles and parse out the targets

src/Runner.Worker/MakefileManager.cs

@@ -0,0 +1,39 @@
+using System.IO;
+using System.Linq;
+
+namespace GitHub.Runner.Worker
+{
+    public static class MakefileManager
+    {
+        // Convert the `all` target to a set of steps of its dependencies.
+        // Does not recurse into the dependencies of those steps.
+        public static ActionDefinitionData Load(IExecutionContext executionContext, string makefile, string target)
+        {
+            var targetToFind = target + ":";
+            var lines = File.ReadLines(makefile);
+            string targetLine = lines.FirstOrDefault(line => line.TrimStart().StartsWith(targetToFind));
+            if (targetLine is null)
+            {
+                return null;
+            }
+
+            var dependencies = targetLine.Split().Skip(1).ToList();
+            if (dependencies.Count == 0)
+            {
+                return null;
+            }
+
+            return new ActionDefinitionData
+            {
+                Name = $"make {target}",
+                Description = "Execute a Makefile target",
+                Execution = new MakefileExecutionData
+                {
+                    Targets = dependencies,
+                    InitCondition = "always()",
+                    CleanupCondition = "always()",
+                }
+            };
+        }
+    }
+}