user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/tests/rtld/scope2/libbar.c

@@ -0,0 +1,5 @@
+char *foo_baz_conflict(void);
+
+char *bar_calls_foo_baz_conflict(void) {
+	return foo_baz_conflict();
+}