Log Message:
mksh: Import unpacked mksh-59b sources.

Two patches have been applied on top, both of which are stored in the
patches directory as manual-Build.sh and manual-funcs.c, to fix issues
on Darwin and SunOS that will be included in the next mksh release.  The
binary mksh.ico file has been manually removed.

This paves the way for  mksh to be used as an alternate bootstrap shell
instead of shells/pdksh, which has been unmaintained for many years and
has some known issues.

Initial bulk build results on Darwin and SunOS look good, and having a
maintained shell which focuses on portability and speed should provide
us with a better long-term option for systems which require a bootstrap
shell.