thumbnailer FTBFS on arm64 ppc64el

[Timo Jyrinki]

See bug #1613561.

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still ftbfs on arm64 and ppc64el, where it built before:
https://launchpad.net/ubuntu/+source/thumbnailer/2.4+16.10.20160825-0ubuntu1
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For the record, the so far included post-5.6.1 QDBus patches in our packages:

https://codereview.qt-project.org/#/c/167480/
https://codereview.qt-project.org/#/c/170356/

Thiago is the main contact in upstream.
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We had also problems with telepathy-qt and signon with QDBus, but two patches were landed that made QDBus ok with those. However, do note that the QDBus rewrite in Qt 5.6 from event loop based to threaded might easily require changes in our code, as it did for telepathy-qt:

http://launchpadlibrarian.net/280893997/telepathy-qt_0.9.6.1-6ubuntu1_0.9.6.1-7ubuntu2.diff.gz
http://launchpadlibrarian.net/284273846/telepathy-qt_0.9.6.1-7ubuntu2_0.9.6.1-9ubuntu6.diff.gz

Maybe those could give some ideas on what to change in thumbnailer?

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...although the thumbnailer problems seems a bit different as it's limited to two rarer 64-bit architectures instead of happening on all of them.

[Timo Jyrinki (timo-jyrinki)]

It starts to look like it's not from Qt code exactly, as the those pass on xenial overlay which has identical Qt versions, but fail on yakkety:

https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/1968/+packages
https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/1969/+packages

It might be related to glibc 2.24 or GCC6, or how Qt behaves with those.

[Michi Henning (michihenning)]

After discussions with mterry and alecu, we decided to disable the failing tests on xenial and yakkety. The linked branch does this.

I've opened a separate bug to make sure we don't forget to turn those tests back on:

https://bugs.launchpad.net/ubuntu/+source/thumbnailer/+bug/1626815