bug#4902: 23.1; directory-abbrev-alist is not handled early enough

[Stefan Monnier]

> (setq directory-abbrev-alist '(("^/mount/" . "//uncpath/mount/")))

> Even after setting this value, it is not honored on Windows.
> Lower level functions appear to ignore directory-abbrev-alist,
> so find-file and find-file-noselect etc. end up with "true" filenames that
> contain drive letters:

> (file-truename "/mount/somefile.x")
> => "c:/mount/somefile.x"

file-truename does not use directory-abbrev-alist.
Only abbreviate-file-name does.


        Stefan