user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/tests/rtld/tls_align/test.c

@@ -0,0 +1,12 @@
+#include <assert.h>
+#include <stdint.h>
+
+extern _Thread_local char foo_thread_local[];
+extern _Thread_local char bar_thread_local[];
+
+int main() {
+	assert(!((uintptr_t)foo_thread_local & (16 - 1)));
+	assert(!((uintptr_t)bar_thread_local & (8 - 1)));
+
+	return 0;
+}