Update to 3.20120109. From the changelog:

* mdwn: Can use the discount markdown library, via the
  Text::Markdown::Discount perl module. This is preferred if available
  since it's the fastest currently supported markdown library, speeding up
  ikiwiki's markdown rendering by a factor of 40.
  (However, when multimarkdown is enabled, Text::Markdown::Multimarkdown
  is still used.)
* On Debian, depend on libtext-markdown-discount.

pkgsrc changes:

* Change Perl Markdown dependency to p5-Text-Markdown-Discount.

(schmonz)