In a Qt project on Windows with `set(CMAKE_AUTOUIC ON)` and using the Ninja generator I experience that if a `foo.ui` is touched I need to build twice with Ninja. The first time `ui_foo.h` is produced. The second time `foo.cpp` is compiled (presumably because `ui_foo.h` is updated) and the program linked. With MinGW Makefiles `foo.cpp` is compiled the first time around. This is with CMake 3.7.2. This has been reproduced on Linux as well on master.