bug#5591: 23.1.92; bookmark.el and file path

[Leo]

If you open a file in your home directory and bookmark it, the path in
bookmark list (C-x r l) will be something beginning with ~ for example:
~/Emacs/gtd/Tasks.org.

However, if the directory gtd does not exist and you use bookmark's
relocation to change to a new file, say ~/Emacs/todo/Tasks.org. The path
in bookmark list will be a absolute path:
/home/someone/Emacs/todo/Tasks.org.

Using a absolute path here is not a good idea. For example I sync some
directories between machines and I don't have the same user name on all
of them. And these bookmarks will fail.

Another case. I recently installed Snow Leopard and decided to create a
different user name for myself. But I find out many bookmarks are no
longer valid due to the use of absolute paths.


In GNU Emacs 23.1.92.2 (x86_64-apple-darwin10.2.0, Carbon Version 1.6.0 AppKit 
1038.25)
 of 2010-02-03 on Victoria.local
Windowing system distributor `Apple Inc.', version 10.6.2
configured using `configure  '--prefix=/usr/local/unix/emacs' '--with-mac''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  value of $XMODIFIERS: nil
  locale-coding-system: iso-latin-1-unix
  default enable-multibyte-characters: t

Major mode: Group