`make distcheck'

[Ian Jackson <ian@davenant.greenend.org.uk>]

While preparing 1.15.0, I tripped over `make distcheck' failing.

The purpose of make dist is to be to be able to make a fresh tarball
from a dirty source tree.  However, we can already do that easily
because we have a revision control system.  So asking `make dist' to
work means that we have to manually add new files in one more place,
but without any useful benefit.

I therefore built 1.15.0 with the following process, adapted from the
release process in Teams/Dpkg/GitUsage:
  * Finalise changelogs and commit
  * git-tag
  * autoreconf -f -i
  * dpkg-buildpackage -us -uc -S -rfakeroot
  * pbuilder --build dpkg_1.15.0.dsc

I suggest we change the wiki accordingly and cease to maintain `make
dist' (ie, the corresponding variables in the various Makefile.am's).

Ian.