bug#5297: 23.1; vc: fails to follow symlinks inside HOME

[Yuya Nishihara]

When detecting vc backend, vc-find-file-hook passes buffer-file-truename
to vc-backend function. However, because buffer-file-truename is *abbreviated*,
following vc-hg-registered or vc-git-registered just fails.

Also it seems bad to test equalness of buffer-file-name
and buffer-file-truename. Maybe buffer-file-name is expanded,
but buffer-file-truename is abbreviated.

In GNU Emacs 23.1.1 (x86_64-pc-linux-gnu, GTK+ Version 2.18.3)
of 2009-11-02 on excelsior, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.10605000
configured using `configure '--build=x86_64-linux-gnu' '--host=x86_64-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.1/leim' '--with-x=yes' '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars' 'build_alias=x86_64-linux-gnu' 'host_alias=x86_64-linux-gnu' 'CFLAGS=-DDEBIAN -g -O2' 'LDFLAGS=-g' 'CPPFLAGS=''

Important settings:
value of $LC_ALL: nil
value of $LC_COLLATE: nil
value of $LC_CTYPE: nil
value of $LC_MESSAGES: C
value of $LC_MONETARY: nil
value of $LC_NUMERIC: nil
value of $LC_TIME: nil
value of $LANG: ja_JP.UTF-8
value of $XMODIFIERS: @im=ibus
locale-coding-system: utf-8-unix
default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
show-paren-mode: t
cua-mode: t
tabbar-mwheel-mode: t
tabbar-mode: t
highlight-symbol-mode: t
hi-lock-mode: t
global-linum-mode: t
linum-mode: t
hl-line-mode: t
tooltip-mode: t
mouse-wheel-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
global-auto-composition-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
temp-buffer-resize-mode: t
size-indication-mode: t
column-number-mode: t
line-number-mode: t
transient-mark-mode: t

Recent input:
M-x r e p o r <tab> <return>

Recent messages:
Loading /etc/emacs/site-start.d/50php-elisp.el (source)...done
Loading /etc/emacs/site-start.d/50psvn.el (source)...done
Loading /etc/emacs/site-start.d/50pymacs.el (source)...done
Loading /etc/emacs/site-start.d/50python-docutils.el (source)...done
Loading /etc/emacs/site-start.d/50python-mode.el (source)...done
Loading /etc/emacs/site-start.d/50ruby1.8-elisp.el (source)...done
Loading /etc/emacs/site-start.d/50yaml-mode.el (source)...done
Loading cua-base...done
Loading paren...done
For information about GNU Emacs and the GNU system, type <f1> C-a.