I have a simple CMakeLists.txt that looks like this:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
PROJECT(calculator)
FIND_PACKAGE(Qt5Core)
FIND_PACKAGE(Qt5Gui)
FIN
I have encountered the same issue on Mac OS X. Ui form header file is not generated.
I have solved my problem by generating manually .h file with QtDesigner. When changes are made on ui form, header file is well generated.
Note: if I add some others ui forms, headers are generated automatically without needed to generate header file manually for these others ui.
EDIT: header file is well generated at first build only if it isn't used into cpp code.