After further discussion after
daa9fe8a, reorder the version-specific
sections from oldest to newest.  Also, remove the variable assignments
from PQfnumber() to reduce vertical space.
Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
Discussion: https://www.postgresql.org/message-id/flat/6594334b-40fd-14f1-6bc5-877afa3feed5@2ndquadrant.com