I have cloned the emacs git repo. What i am trying to do is modify it so that site-list.el contains a line of code telling emacs to load my custom emacs lib on load. But i would like to do it in a branch so that i can keep up with the bug fixes but every time i build it it gets build with my custom site-lisp file.
But i can not seem to pinpoint where the file is or where it is created?
I'd set it up like this:
git clone <repository>
git checkout -b my-work # do all your work on the my-work branch.
<do some work>
git add <list of new files>
git commit
When it comes to updating from the remote repository:
git checkout master # keep a clean master branch free from your changes
git pull
git checkout my-work
git merge master
My point is to take some care to keep a clean branch and a separate development branch. Also remember git pull = git fetch + git merge so you need to take care which branch you have checked out when you pull.
There is a great article on working with Git from Emacs by Alex Ott introduces the main packages providing an interface for git. Personally I prefer magit but in your case I suggest it to you as well, since managing branches is very convenient with it.