On 8/7/2012 1:01 PM, Stefan Monnier wrote:
>> But then the code that defvars the variable needs to know about all
>> the window systems we might use. It seems cleaner to have the
>> window-system-specific code add the window-system-specific alist entries.
> 
> But they all need to know about each other to avoid conflicts anyway.

Not really --- different window-systems just need to avoid having the same
display-string prefix. This approach works well enough in other pieces of code:
org-mode doesn't need to know about cc-mode specifically in order not to trample
on cc-mode's namespace.