Bug#758100: versioned provides coming up for perl 5.26

[Niko Tyni]

Update on versioned provides and perl: we discussed this at the 2017
Perl team sprint in Lloret de Mar, and it looks like all the blockers
for this have been resolved. I intend to switch to versioned provides
for the upcoming 5.26 packages, targeted for buster. 

This starts a soft transition where all packages with alternative
dependencies like

perl (>= x) | libfoo-bar-perl (>= y)
libfoo-bar-perl (>= y) | perl (>= x)

can be changed to use just the libfoo-bar-perl (>= y) part.

The alternative dependency on perl was always just an optimization to
avoid needlessly installing the separate package when it was already
recent enough in the core. With versioned provides this optimization
is no longer necessary.

The plan is to push this into experimental soon, then test rebuild
packages as usual to verify that nothing is clearly broken. After that,
I intend to raise this one more on debian-devel@ and possibly with
the release team, in case somebody's aware of any more blockers in the
archive infrastructure etc.
-- 
Niko Tyni  ntyni at debian.org