Bug#878356: cross-gcc-dev should support gcc-8

[Helmut Grohne <helmut@subdivi.de>]

Package: cross-gcc-dev
Severity: important
User: helmutg@debian.org
Usertags: rebootstrap

Please add support for gcc-8. That can have multiple forms, each of
which has its own benefit:

a) Just copy the gcc-7 patches to gcc-8 and hope for the best.
b) Make the patches apply to the gcc-8 source package.
c) Verify that a cross compiler can be built.

a) has close to zero effort, b) likely takes an hour or so and c)
longer. If you can do b), that'd be very useful already, but even a)
helps. I'm happy to file followup bug reports with patches. The earlier
we start, the less work we'll have. Go go.

Helmut