If this is still a llive issue for you:
Look in the makefile and its 'headers'; either the makefile directly moves/copies the installed files like:
mv ./bin/mozillabin /usr/bin/mozilla
or it uses defines replacing the above with something like :
mv MAKEBIN_DIR/mozillabin TARG_RUN_DIR/mozilla
having defined the all-caps elsewhere at the top-ish uf the makefile or in its 'headers'
Open an editor, copy the needed info on whatever gets send outside the build-dir chain into the editor, munge around as needed to create delete commands for those things, then y'all can e.g.: pasted into a terminal (xterm, etc) to execute, and when you're done, erase the build dir-chain since it sounds like you're through with it.