[PATCH] Makerules: run test-container helper through the built loader

[Florian Weimer]

* Adhemerval Zanella:

> The tests-container rule launches support/test-container, which is always
> dynamically linked, through $(test-via-rtld-prefix).  That prefix is empty
> for tests listed in tests-static/xtests-static, so for a static container
> test the helper ran under the system loader/libc instead of the newly
> built one.

Why not use $(rtld-prefix) directly?  I think we already do this in
other places.

Thanks,
Florian