our project contains lots of autogenerated Qt files and when reading the
3.9 Release notes I was very excited about the new AUTOGEN_BUILD_DIR
property to speed up the build times (for constantly bulding debug and
release versions in case nothing has changed).
But it seems I cannot get it to work properly with MSVC 14 2015 and a
config dependent AUTOGEN_BUILD_DIR.
My CMakeLists.txt basically looks the following way: