Bug 405506

SUMMARY
Please describe specifically how to build the package from source on Windows or *nix.  Ideally this would go in INSTALL; alternately it could go in the README.  This would start with a list of prerequisite software, where to obtain it, and whether source or binary versions were necessary.  It would then describe environment setup and build steps.

DETAILS
The current source code (git://anongit.kde.org/kdiff3.git) does not explain in any specific way how to build the package on either Windows (my current concern) or *nix.

INSTALL is simply a pointer to the README, which has some general remarks about requirements at the top.  The old, specific, instructions were deleted as obsolete, but they haven't been replaced by anything. It doesn't even indicate which specific KF5 frameworks are required.

Maybe this is all obvious to those familiar with cmake or KF5, but it's not obvious to me.  The old INSTALL recipe of configure; make; make install was "obvious" to those familiar with it, but it was still documented in INSTALL.  I'm hoping  for something similar.

https://community.kde.org/Guidelines_and_HOWTOs/Build_from_source/Windows has been only marginally helpful.  Having followed the steps, I'm not even sure if I've completed them properly or not (the last thing was the message 
Execute: C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\python.exe c:\Users\rdboylan\Documents\src\CraftRoot\craft-master\bin\craft.py craft
Please ensure that you have installed the C++ component
).  And it was also unclear to me from those instructions whether it would suffice to download the Qt binaries.