shells/ast-ksh fails to build on NetBSD

[Benny Siegert <bsiegert%gmail.com@localhost>]

As far as I can tell from the bulk results in bulktracker.appspot.com,
the last release on which ast-ksh worked was NetBSD 6. My build on -8
fails in exactly the same way as the build log at
http://ftp.netbsd.org/pub/pkgsrc/packages/reports/2018Q1/NetBSD-8.0-x86_64/20180621.1349//ast-ksh-20120801nb2/build.log.

Any ideas?

I saw that our ksh version is from 2012, while there seems to be a
newer one (from 2017) available on https://github.com/att/ast.

-- 
Benny