Fix automagic detection of Qt5
Hello.
Right now kid3 build system has a hack to detect Qt5. Which does NOT allow to control whether kid3 is build against Qt4 or Qt5. cmake provides regular find modules to detect the both Qt major versions. So a build option is needed and the usage of the correct find modules.
Automagic Qt detection could be fine on binary distros, but can cause problems on source-based ones like Gentoo.
The related snippet of code from /CMakeLists.txt:
set(QT_EXECUTABLE_COMPILE_FLAGS) string(REGEX MATCH "^(.[Qq]t5.).bin.qmake.*" _qt5Dir "${QT_QMAKE_EXECUTABLE}") if (_qt5Dir) set(_qt5Dir ${CMAKE_MATCH_1}) endif (_qt5Dir)
See also https://bugs.gentoo.org/show_bug.cgi?id=471974#c7
Imported from SourceForge, author: nobody