Found this in trying to make a qtwebengine-5.8 build for f25/f26 on top of Qt-5.7, found at least one hard-coded reference to 5.8.0 in /usr/lib64/cmake/Qt5WebEngineCore/Qt5WebEngineCoreConfig.cmake find_package(Qt5${_module_dep} 5.8.0 ... We'll likely want to patch/modify that to relax to match actual Qt5 version used (5.7.1 in this case).
%changelog * Mon Apr 10 2017 Rex Dieter <rdieter> - 5.8.0-8 - Qt5WebEngineCoreConfig.cmake: fix when using Qt < %%version (#1438877)