[MacPorts] #70673: autoconf fails on Linux if help2man not installed, but no dependency on it

[MacPorts]

#70673: autoconf fails on Linux if help2man not installed, but no dependency on it
---------------------------+----------------------
  Reporter:  barracuda156  |      Owner:  larryv
      Type:  defect        |     Status:  assigned
  Priority:  Normal        |  Milestone:
 Component:  ports         |    Version:  2.10.1
Resolution:                |   Keywords:  linux
      Port:  autoconf      |
---------------------------+----------------------
Changes (by ryandesign):

 * owner:  (none) => larryv
 * status:  new => assigned


Comment:

 `help2man` is provided by by macOS so this problem was not noticed on
 macOS.

 I thought the correct solution would be to declare `depends_build
 bin:help2man:help2man` so that the macOS copy of `help2man` could satisfy
 it. But I can't find any other ports doing that and no evidence that any
 ports ever did so which surprises me. All ports that depend on help2man do
 so as `port:help2man` which will unconditionally pull in help2man and its
 dependencies which may be undesirable for a port like autoconf that is
 foundational for the builds of many other ports. At present help2man and
 its recursive dependencies don't depend on autoconf but it's conceivable
 that in the future they might need to which would introduce a dependency
 cycle.

-- 
Ticket URL: <https://trac.macports.org/ticket/70673#comment:2>
MacPorts <https://www.macports.org/>
Ports system for macOS