spew is a 9front user who wanted to improve awk. there is no separate hg location, branch, etc., awk is in the default branch of 9front.
i don't know if he wasted a thought on unix while he was doing that, better ask him: he's on #cat-v on freenode regularly. the 9front distribution .iso contains the complete hg repo with all the history, so if you can run our awk, you also have the source and the history. his efforts started with the regexp library that used to require ape! the first related commits i found are: changeset: 5271:9bf761f83f7e branch: spew user: ben@rana date: Wed Apr 27 07:52:41 2016 -0500 summary: remove ape regexp library, add utility for awk native port changeset: 5269:cad63b966180 branch: spew parent: 5266:682b1efdef40 user: ben@rana date: Tue Apr 26 22:23:44 2016 -0500 summary: New libregexp and APE ported to native replying to list in case others want to understand, too.
