Re: improved mh-chart man page

[Ken Hornstein]

>I vote to stay with backticks.  We've maintained (or at least tried to
>maintain) Bourne shell throughout the rest of nmh, and I think we
>should keep it that way.

Officially, $(...) is part of POSIX; it's not a Bash-ism.

https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html

We USED to use $(...) in the test suite.  But that was dropped because
it turns out that /bin/sh on Solaris does not support that (at least, that
was my memory).  I am neutral about whether or not we should continue
to support ancient shells.

--Ken