[linux] "Failed to load platform plugin "xcb" " while launching qt5 app on linux without qt installed

In my case missing header files were the reason libxcb was not built by Qt. Installing them according to https://wiki.qt.io/Building_Qt_5_from_Git#Linux.2FX11 resolved the issue:

yum install libxcb libxcb-devel xcb-util xcb-util-devel mesa-libGL-devel libxkbcommon-devel