[Soc-coordination] Declarative Diversions - Report 1

[Jonathan Nieder]

Luk Claes wrote:

> Because people want to have both atomic changes of their /bin/sh as well
> as being able to choose between more than 2 options for their /bin/sh ...

See http://repo.or.cz/w/dash/debian/jrn.git/commitdiff/cea77edd1 for
an example where the ability to atomically "steal" a diversion would
be helpful.  This is certainly not a candidate for declarative
diversions (and the tricky use of diversions is just meant as a means
of escape from a scenario where diversions were not the right tool for
the job imho).