[MacPorts] #54118: Keep more old versions of postgresql9* in postgis2

[MacPorts]

#54118: Keep more old versions of postgresql9* in postgis2
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 Reporter:  JDLH    |      Owner:
     Type:  defect  |     Status:  new
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:
 Keywords:          |       Port:  postgis2
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 Postgis2 has variants of form +postgresql96 to target the installed
 PostGIS extension to the desired version of PostgreSQL.  Mac Ports offers
 versions of PostgreSQL from 9.0 to 9.6.

 Postgis2, [https://github.com/macports/macports-
 ports/commit/03c7f226c2e8c714333cffb7c663cca8dc4ec501#diff-
 d2a7900b82d37c47c3769ef8bd7b84b0 Commit 03c7f22],Oct 25, 2016, removed the
 variants postgresql93 and postgresql94 because the are "obsolete PGsql
 versions".  I don't see a comment in the commit or in a ticket that the
 current version of PostGIS2 does not work with these versions of
 PostGreSQL, just that they are obsolete.

 It turns out I'm working on a project now which uses PostgreSQL 9.4 as its
 primary version. They are only beginning to experiment with PostgreSQL
 9.6.  Thus I'd suggest that 9.4 is not yet "obsolete" for this shop. Even
 9.3 may be in use somewhere.

 I'd like to suggest that the postgresql94 variant be restored. I'd even
 suggest restoring postgresql93, though that isn't so important for my
 current need.

 Workaround: follow the instructions in the
 [https://trac.macports.org/wiki/howto/InstallingOlderPort MacPorts HOWTO
 "Installing Older Port"] to build commit [https://github.com/macports
 /macports-ports/commit/21a176a68d7895643bff7b740ef0e91ee4eba318 21a176a],
 and install that with `sudo port install +postgresql94 +raster +topology`.

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Ticket URL: <https://trac.macports.org/ticket/54118>
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