Add mt-helloworld example

tests/marchid.h

@@ -0,0 +1,17 @@
+#ifndef MARCHID_H
+#define MARCHID_H
+
+const char* get_march(size_t marchid) {
+  switch (marchid) {
+  case 1:
+    return "rocket";
+  case 2:
+    return "sonicboom";
+  case 5:
+    return "spike";
+  default:
+    return "unknown";
+  }
+}
+
+#endif