SVR4 emulation

[Joerg Sonnenberger <joerg@xxxxxxxxxxxxxxxxx>]

Hi all,
tonight I remembered one problem with the ELF branding -- no branding
and svr4 branding are the same. This means that ATM svr4 support in
HEAD is broken. There is an easy fix possible, but given that the
svr4 emulation is pretty much unmaintained, I'd like to ask whether
we want to continue supporting it at all.

Joerg