time to stop replacing install-sh in/from automake?

[Greg Troxel <gdt%lexort.com@localhost>]

I found a problem building nut (sysutils/ups-nut) from git, where `make
-j6 install` would invoke the install-sh produced by automake multiple
times.  This ought to do mkdir -p, which should work, but install-sh is
replaced by pkgsrc and does not use -p.

There is a comment about this install-sh, rather than the one which
comes with automake, being needed by Interix.  The Interix readme in
bootstrap was last updated in 2016, and it seems to be an obsolete UNIX
layer for no-longer-supported Windows versions, last released in 2010.
I would guess that:

  - nobody is using pkgsrc on Interix and it probably doesn't really
    work any more
  - anyone using Interix has had ample time to report this to automake
    and submit a fix

As it is, the automake built by pkgsrc installs an install-sh which is
non-standard and apparently defective, so that doing "make dist" on a
pkgsrc system and distributing it is not ok.

I haven't really analyzed, but it seems to me we should just stop
replacing install-sh, except maybe on specific platforms, as a
workaround for those platforms not having upstreamed a fix.

Is there more to this than that?