[PATCH setup] Allow setup to parse more than 3 versions from the setup.ini file

[Jon Turney]

On 09/10/2017 20:32, Jon Turney wrote:
> So, thinking about this change some more, I realize that there is a 
> another way to do this, which doesn't break backwards compatibility with 
> setup, by having multiple [prev] and [test] sections.
> 
> [1] doesn't say that these section names are unique, and setup doesn't 
> require that, I'm going to claim that it's valid :)
> 
> Because of the way setup works, the last [test] section is the version 
> which is selected when 'test' is selected, so a specific ordering of the 
> sections would be required.  The calm change to implement this is at [2].
[...]
> [1] https://sourceware.org/cygwin-apps/setup.ini.html
> [2] https://github.com/jon-turney/calm/commit/c21cfdc8f8c94f615ff97000428c6e542d335dca 

I deployed this calm change today.

I think that no-one should notice anything, apart from setup now 
offering another choice of older versions for some packages.

The current default package retention policy is: the curr and test 
versions are always kept, also keep the 3 highest versions (this is 
slightly more generous than upset's historical behaviour, as it keeps 3 
versions even if test isn't being used)

Maintainers can customize this policy using keep*: lines in 
override.hint [3].

[3] https://cygwin.com/packaging-hint-files.html#override.hint