Solaris BF owners, please consider adding --with-pam

The discussion around bug #18995 [1] revealed that no current
Solaris or Solaris-descendant buildfarm animals build with
PAM support.  We might have noticed that bug sooner if any
did, so if you run such an animal, please consider enabling
that option.

            regards, tom lane

[1] https://www.postgresql.org/message-id/flat/18995-82058da9ab4337a7%40postgresql.org