New S/390 machine maintainer: Stefan Liebler

[Andreas Krebbel]

Hi,

Stefan Liebler takes care of the S/390 specific parts of Glibc for quite a while now.  He is doing a
good job and has already implemented major features (e.g. z13 string instruction support).

I think it is time to appoint him machine maintainer for S/390.

Ok to add him to the machine maintainers list for S/390 in the wiki?

Martin Schwidefsky and myself will stay in the list as well for now.

-Andreas-