aptitude: display, search by “Supported:” field

[Daniel Hartwig]

Forwarded request from [1] as it is specifically of interest to Ubuntu users. I presume that support has been implemented in USC or whatever is package-manager-of-the-day; what about the rest of main?

[1] http://bugs.debian.org/606546

[Original Description]

Canonical places a "Supported" field in their Packages files, indicating how long they (nominally) provide support for the package in question. I can show this field in search results:

    $ grep-aptavail -ns Package,Supported -F Provides x-display-manager | fmt | tr -s '\n'
    kdm 3y
    lxdm
    slim
    wdm
    xdm
    gdm 3y

and I can search by it (doesn't actually work in grep-status):

    $ grep-status -ns Package -F Supported 5y

I would like to do these things in aptitude instead of dctrl-tools. For that to work, I think aptitude needs a search term (e.g. ?supported(5y)) and a format string (e.g. %L) for the Supported field.