Makefile: Add few src file for testing

Makefile/bin.cpp

@@ -0,0 +1,8 @@
+#include <iostream>
+#include "lib.h"
+
+int main(int argc, const char *argv[])
+{
+	std::cout << "C++ Hello World!" << std::endl;
+	return 0;
+}

Makefile/lib.c

@@ -0,0 +1,3 @@
+#include "lib.h"
+
+void lib() { return; }

Makefile/lib.h

@@ -0,0 +1,3 @@
+#pragma once
+
+void lib();

Makefile/main.c

@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include "lib.h"
+
+int main(int argc, const char *argv[])
+{
+	printf("Hello world\n");
+	return 0;
+}