auto-pkgsrc-setup on SunOS

[Jason Bacon <jtocino%gmx.com@localhost>]

FYI, in response to a bug report for one of my packages when building on
SunOS, I cleaned up and tested auto-pkgsrc-setup on OpenIndiana.

The standalone script is available at http://netbsd.org/~bacon/.  It's
also part of sysutils/auto-admin.  The latest is in wip/auto-admin.

Please let me know if it works or does not on other Solaris-based
platforms.  For OpenIndiana, I got started by running pkg update,
rebooting to load the new boot env, and then running

pkg install developer/gcc-10 git openjdk18 gnu-tar

This pkg install fails for a fresh hipster 2021-10 install.  It needs to
be updated first.