Importing mksh in base

[Garrett Wollman]

In article <201901270019.x0R0JpF4096103 at pdx.rh.CN85.dnsmgr.net> you write:

>Doesnt pdksh have a "sh" compatible mode iirc when you
>invoke it via a path of sh it behaves as a traditional
>bourne shell, also if IIRC Openbsd is doing just that,
>/bin/sh -> /bin/pdksh (hard link)

POSIX specifies the shell to be ksh88 (with some modifications for
locale support).

ksh93 has some different behavior from ksh88, but most (not all) of
the ways in which it differs are compatible extensions to the POSIX
shell.  (The reason it's still called ksh93 today has to do with
internal corporate legal bureaucracy that made it easier to release
"updates" than a new "version".)  Both the Almquist shell (which is
the ancestor of our /bin/sh) and bash were aligned with the POSIX
specification as it evolved, and the current /bin/sh and bash
maintainers continue to participate in the Austin Group process for
shell standardization.  (Robert Elz, who maintain's NetBSD's version
of the Almquist shell, also participates, as do the author of mksh and
the author of the portable shell scripting library modernish.  David
Korn used to participate but has not been heard from in several
years.)

-GAWollman