pgsql: Remove compiler warning option -Wendif-labels

Remove compiler warning option -Wendif-labels

This warning has always been on by default in GCC (and in Clang at
least going back to 3.1), so we don't need the option explicitly.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: /messages/by-id/aa73q1aT0A3/vke/@ip-10-97-1-34.eu-west-3.compute.internal

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/87e1891c459ecf7aa839de75d8afca3e1a6d154f

Modified Files
--------------
configure | 91 ------------------------------------------------------------
configure.ac | 2 --
meson.build | 1 -
3 files changed, 94 deletions(-)