Disco Dingo test rebuilds

[Matthias Klose]

The first test rebuild of Disco Dingo was started on December 21 2018 for
all architectures, all components.  The number of build time failures
unfortunately is again high, even higher than for the last Cosmic Cuttlefish
test rebuild.

Results (please also look at the superseded builds) can be found at

http://people.canonical.com/~doko/ftbfs-report/test-rebuild-20181220-disco.html

The report uses some additional color coding, marking packages different which
always failed to build, or where the build failure is no regression compared to
bionic.

Additional build failures for packages in disco-proposed (not yet in disco)
can be found at http://qa.ubuntuwire.com/ftbfs/

Please help fixing the build failures.

There is also a test rebuild using an early version of GCC 9, which will become
the default compiler for the 19.10 release. Results at

http://people.canonical.com/~doko/ftbfs-report/test-rebuild-20181220-gcc9-disco.html

Matthias