Build/dev process: rebuild when using custom CMake options

Newbie question: I’m building the cycles-x branch. I need to use a custom CMake option; to do that I edit CMakeCache.txt in my build dir and then do make in there, after having done a full build once to create that build dir.
This works OK. My question is about the best process when I pull new changes from upstream. Can I just do make in the build dir? Or do I have to update anything first?
Really all I’m asking is if the build in the build dir gets its sources & dependencies from the source dir or if I need to do anything after pulling new code.

While this will work most of the time, some small tweaks may be beneficial:

Rather than just git pull i’d recommend running make update in the source folder to account for any changes in addons and/or svn libraries…

for building, I’d recommend running make install rather than just make in your build folder just to make sure if any additional runtime files were added they are copied to the right place.