Bug#766708: breaks multiarch cross building

[Helmut Grohne <helmut@subdivi.de>]

Package: gcc-4.9
Version: 4.9.1-19
Severity: serious
Justification: do not migrate to jessie
User: helmutg@debian.org
Usertags: rebootstrap

Hi Matthias,

I notice that starting with -19 gcc emits unsatisfiable dependencies in
multiarch cross builds regressing from -18. This makes all rebootstrap
builds fail to install gcc. You can find a failed attempt to install at
https://jenkins.debian.net/job/rebootstrap_m68k_gcc49/100/console.

It seems that gcc now emits dependencies on libc-*-$arch-cross, but
glibc doesn't build those.

I'll look into the matter and try to provide a patch.

Helmut