unity FTBFS on powerpc and ppc64el in xenial

[Steve Langasek]

unity is failing to build on powerpc and ppc64el in xenial.

WARN 2015-11-11 20:00:16 unity.screen UScreen.cpp:126 UScreen::GetMonitorName: Failed to get monitor name for monitor0
[==========] Running 1651 tests from 108 test cases.
[----------] Global test environment set-up.
[----------] 14 tests from TestActionLink
[ RUN ] TestActionLink.AligmentCorrectlySetDifferent
Segmentation fault
tests/CMakeFiles/check-headless.dir/build.make:56: recipe for target 'tests/CMakeFiles/check-headless' failed
make[5]: *** [tests/CMakeFiles/check-headless] Error 139

Full build log for powerpc can be found at <https://launchpadlibrarian.net/225846586/buildlog_ubuntu-xenial-powerpc.unity_7.4.0%2B16.04.20151102-0ubuntu2_BUILDING.txt.gz>.

This is blocking a transition of a new libglew soname in xenial, and along with it a large number of other library transitions, so marking as critical.

[Steve Langasek (vorlon)]

This problem has not been reproducible on porter-powerpc, so I've retried the builds in case it's a fluke.

[Steve Langasek (vorlon)]

The package has now rebuilt successfully on both power and ppc64el. So this was either an intermittent or a transient error.