When emerging net-misc/nextcloud-client-3.1.2 (no active useflag) I got this error: CMake Error at /usr/lib64/cmake/Qt5/Qt5Config.cmake:28 (find_package): Could not find a package configuration file provided by "Qt5WebSockets" with any of the following names: Qt5WebSocketsConfig.cmake qt5websockets-config.cmake Add the installation prefix of "Qt5WebSockets" to CMAKE_PREFIX_PATH or set "Qt5WebSockets_DIR" to a directory containing one of the above files. If "Qt5WebSockets" provides a separate development package or SDK, be sure it has been installed. Solved after manually emerging dev-qt/qtwebsockets
*** This bug has been marked as a duplicate of bug 768606 ***