Mac OS/Brew: ccmake does not detect Qt5.15
If you installed qt5 via Brew, then you will get this error:
CMake Error at /usr/local/lib/cmake/Qt5Core/Qt5CoreConfig.cmake:15 (message): The imported target "Qt5::Core" references the file
"/usr/local//mkspecs/macx-clang"
Solution: change the qt5_dir to your proper. In my case it was
/usr/local/Cellar/qt/5.15.2/lib/cmake/Qt5
Change the location for other generated qt5 as well.
If you have Anaconda installed. Chances are it will pick up qt5.9 from conda, which is not supported. Uninstall qt5.9 from conda