Re: abbreviate-file-name on Windows seems incorrect

[Richard Stallman]

    > Can you check whether the efficiency gain is really significant in
    > practice?
    Compared with the current version of abbreviate-file-name, getenv seems 
    to take a little more than twice as long to complete on my system. So it 
    might be reasonable to expect the time for abbreviate-file-name to 
    triple if it is changed to calculate the value of HOME every time it is 
    needed based on getenv alone.

Ok, that is enough reason to keep it the way it is.