Re: master daea9b3 1/2: Read mailcaps again only when necessary

[Stefan Monnier]

> Once again, the key for recording the time stamp is the file name you
> pass, so that key must be unique, and that means file-truename.

I'm not sure `file-truename` is indispensable or even desirable.
E.g.:

- read file ~/fileA which is a symlink to /foo/A,
  with `file-truename` when `file-changed-p` is called it records that
  /foo/A has timestamp T1.
- read ~/fileB which is a normal file.  When `file-changed-p` is called it
  records that ~/fileB has timestamp T2.
- user changes ~/fileB into a symlink to /foo/A
- we go and check whether ~/fileB has changed: when `file-changed-p` is
  called it passes it to `file-truename` before it looks up the
  hash-table; it then sees that it's still T1 and will say "everything
  good, ~/fileB hasn't changed".


-- Stefan