[PostGIS] #5757: pgSQL 17 json support prevents compile

[PostGIS]

#5757: pgSQL 17 json support prevents compile
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 Reporter:  robe     |      Owner:  pramsey
     Type:  defect   |     Status:  new
 Priority:  blocker  |  Milestone:  PostGIS 3.4.3
Component:  postgis  |    Version:  3.4.x
 Keywords:           |
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 Okay they had put back that SQL JSON support back in PG17.  So need to
 change that IF DEF, cause now even master doesn't work against released
 PG17
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Ticket URL: <https://trac.osgeo.org/postgis/ticket/5757>
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