pkgsrc change: Add pkg_alternatives support.
== 1.6.3 Protein Powder
* Add HTTP 422 status code [rajcybage]
* Add warning about EM reactor still running when stopping.
* Remove version number from "Server" HTTP header. [benbasson]
* Adding `--ssl-disable-verify` to allow disabling of client cert requests when SSL enabled [brucek]
* Ensure Tempfiles created by a large request are closed and deleted. [Tonkpils]
