🚀 go-pugleaf

I'd like to make the lisp startup files such as site-init.el and default.el
do different things depending on the OS type.   SYSTEM_TYPE is currently the
same for several systems that I want to be able to tell apart.  I'm looking
to minimize the changes I'd have to make to other lisp files.

Looking for "magic" files or groveling through the kernel would be
the last resort.

What is the cleanest way to do this? - I imagine I could come up with
new unique names for OS/platform combinations, for example:

   (if (eq system-type 'encore-berkeley-unix)

       then fix encore problems

       else do sun specific things

Or should I make up a new variable to suit my purpose?
I mainly want to differentiate between systems currently known as 
"berkeley-unix".

Thanks
-e