generalize -scheduler=none to support most platforms

src/runtime/scheduler_none.go

@@ -12,3 +12,11 @@ func sleep(duration int64) {
 func getSystemStackPointer() uintptr {
 	return getCurrentStackPointer()
 }
+
+// run is called by the program entry point to execute the go program.
+// With the "none" scheduler, init and the main function are invoked directly.
+func run() {
+	initAll()
+	postinit()
+	callMain()
+}