How to get UE4 source build on linux to recognize changed files and rebuild

I backported a trivial fix from 4.20 to 4.19, inside the CMakefileGenerator.cs file to fix Linux project makefile defects preventing CLion from indexing my game.

How in the world do I get the UE4 source build system to detect that I’ve changed the .cs file, rebuild that tool, and rebuild all the makefiles. I’ve tried running, and that runs but doesn’t seem to change anything. It doesn’t look like it recompiled the makefile generator.

I don’t see anything like a make clean. And I can only find documentation on how to build UE4 the first time, not how to loop the edit-build-test-edit cycle.

I deleted UnrealBuildTool.exe, and rebuilt… then re-ran it on my game to generate the project files there. Seems to be working okay, but I’d still like to know what’s the general process for doing a new build of the engine.