Common code for personal settings that aren't dependent on usernames or system-names

[tariqk]

So right now I'm currently using my own copy of the starter kit, and one of the things that I've been noticing is that I really enjoy having a set of common customizations that would normally be used on all the machines I use emacs on, regardless of system-name and user-login-name (they're slightly different on some machines I use).

These days I normally have a system-specific configuration that calls these common customizations first before running through the rest of the system-specific configuration, but since both files are getting longer and longer the more I work through them, I'd rather find a way that doesn't feel so brittle and hackish… most of the time when I install emacs to a new machine I have to find the nearest equivalent to the machine setting I want, copy that file into $SYSTEM-NAME$.el, and then go from there. I've encountered some problems trying to figure out what goes where now.

What would be a good way to, say, group the settings I want based on what applies to all (or almost all) systems I work in, versus, say, stuff that's specific to a particular system? I've seen ways to load different settings based on OS type, but once I have a common place to run things, that should be just a matter of digging through the relevant stackoverflow threads.