Move repositories to 'repos/' subdirectory

This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.

Issue #1082

repos/demo/src/lib/mini_c/malloc_free.cc

@@ -0,0 +1,50 @@
+/*
+ * \brief  Mini C malloc() and free()
+ * \author Norman Feske
+ * \date   2006-07-21
+ */
+
+/*
+ * Copyright (C) 2006-2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#include <base/env.h>
+#include <util/string.h>
+
+using namespace Genode;
+
+
+extern "C" void *malloc(unsigned size)
+{
+	/*
+	 * We store the size of the allocation at the very
+	 * beginning of the allocated block and return
+	 * the subsequent address. This way, we can retrieve
+	 * the size information when freeing the block.
+	 */
+	unsigned long real_size = size + sizeof(unsigned long);
+	void *addr = 0;
+	if (!env()->heap()->alloc(real_size, &addr))
+		return 0;
+
+	*(unsigned long *)addr = real_size;
+	return (unsigned long *)addr + 1;
+}
+
+
+extern "C" void *calloc(unsigned nmemb, unsigned size)
+{
+	void *addr = malloc(nmemb*size);
+	memset(addr, 0, nmemb*size);
+	return addr;
+}
+
+
+extern "C" void free(void *ptr)
+{
+	unsigned long *addr = ((unsigned long *)ptr) - 1;
+	env()->heap()->free(addr, *addr);
+}