Bug#2630: emacs package needs to break ctags-related files out separately

[Bill Mitchell <mitchell@mdd.comm.mot.com>]

Package: emacs
Version: 19.30-1

This package installs /usr/bin/ctags and /usr/man/man1/ctags.1.
These files are also installed by the elv-ctags package.  Elv-ctags
provides its version of the the ctags program along with a companion
program named ref(1). The elvis vi clone uses the ref(1) program to
scan tags files produced by ctags(1).  elv-ctags currently declares a
conflict with emacs becuase of the collision with the ctags files.
This either prevents emacs from being installed if the elv-ctags
package is installed to make its ctags and ref programs available
to elvis, or prevents the elv-ctags package being installed if the
emacs package is installed.

My understanding is that, in order to avoid this, emacs should break
the ctags files out into a separate binary package, perhaps named
emacs-ctags.  elv-ctags should then break the ctags and ref programs
out into two separate binary packages.  Both the emacs-ctags and
the elv-ctags packages should declare conflicts with one another,
and should declare that they "Provide" a virtual package named ctags.
The elv-ref package should declare a dependency on ctags.

Alternatively to declaring conflicts, the elv-ctags and the emacs-ctags
packages might use the /usr/sbin/update-alternatives facility to allow
both elv-ctags and emacs-ctags to install ctags programs under those
names, and to make one of the two alternatives available for invocation
under the ctags name.  As the elvis maintainer, I'm amenable to whichever
solution suits the emacs maintainer.