After upgrading to the PyQt 5.12 wheel on Travis, I got an abort() when
trying to create a QApplication:
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in ".../site-packages/PyQt5/plugins/platforms" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
After debugging this via QT_DEBUG_PLUGINS=1, I found out the xcb plugin
couldn't be loaded due to a missing libxkbcommon-x11.so.0.
This can be fixed by telling Travis to install it:
Still I wonder where that new dependency is coming from - I guess that's
a change in Qt? That library isn't required with 5.11:
$ ldd ./PyQt5-5.11.3-5.11.2-cp35.cp36.cp37.cp38-abi3-manylinux1_x86_64/PyQt5/Qt/plugins/platforms/libqxcb.so | grep libxkb