configure scripts and packaging (gconf, scrollkeeper, etc)

[Jan de Groot <jan jgc homeip net>]

When packaging gnome stuff with make DESTDIR=$somedir/pkg install, many
packages are updating my scrollkeeper database, installing a mime
database, updating my freedesktop.org desktop-database specs, register
gconf schema files, etc on my local system.
Almost every package has a --disable-schemas-install option, but half of
them are hardly working, because the conditional is set in the
Makefiles, but never used after that.

Another thing is the scrollkeeper database: there is no option to
disable scrollkeeper database generation, which results in a nice and
shiny updated scrollkeeper database on your host system, or with gnome
source tarballs updated with new automake, a nice and shiny scrollkeeper
database included in your package. Currently I wreck out the
scrollkeeper things with some find and sed functions from the
Makefile.in before I run ./configure.

Same as for update-mime-database and update-desktop-database: I have to
define the variable to /bin/true to skip generation on packages that do
generate these databases. I have only seen one or two packages that
allow to disable the database stuff.

It would be nice to have consistency across the gnome buildscripts used
in the various source tarballs, the current stuff is not foolproof as it
is now.