Well, here you have a solution for Windows: How to find qt5 CMake module on windows
set (CMAKE_PREFIX_PATH "C:\\Qt\\Qt5.0.1\\5.0.1\\msvc2010\\")
For your environment, I think you will have to change the path where Qt is located…
Maybe this will help you:
https://github.com/Cockatrice/Cockatrice/issues/205