PX4 and Qgroundcontrol build with Qt on OS X

It seems that one can’t build both PX4 and Qgroundcontrol with Qt Creator on one Mac due to different version requirements. While Qgroundcontrol needs XCode 7.3.1 and not newer:

...    
OSX: OSX 10.7 or higher, 64 bit, clang compiler (IMPORTANT: XCode 8 not supported due to Qt bug. Currently only workaround is to use XCode 7.3.1)    
...    

PX4 Qt build asks XCode 8

$ cmake .. -G "CodeBlocks - Unix Makefiles"
-- posix-sitl-default
-- CMAKE_INSTALL_PREFIX: /usr
-- cmake module path: /Users/sagaris/dev/px4/Firmware/cmake
...
CMake Error at cmake/posix/px4_impl_posix.cmake:192 (message):
  PX4 Firmware requires XCode 8 or newer on Mac OS.  Version installed on
  this system: 7.3.0.7030031
Call Stack (most recent call first):
  CMakeLists.txt:338 (px4_os_add_flags)

-- Configuring incomplete, errors occurred!
See also "/Users/sagaris/dev/px4/Firmware/build_creator/CMakeFiles/CMakeOutput.log".    

So is there any workaround to use one Mac with Qt for both project development?

The QGC README is wrong. You can use XCode 8. You just need to use the workaround which is described further down the README.