pgsql: pg_plan_advice: Always install pg_plan_advice.h, and in the righ

pg_plan_advice: Always install pg_plan_advice.h, and in the right place

The Makefile failed to set HEADERS_pg_plan_advice, so the header wasn't
installed. Fixing that reveals another problem: since this is just a
loadable module, not an extension, the header file is installed into
$(includedir_server)/contrib rather than $(includedir_server)/extension.
While we have no existing cases of installing header files there, it
appears to be the intent of pgxs.mk. However, this is inconsistent with
meson.build, which was using dir_include_extension. Changing that to
dir_include_server / 'contrib' makes the install locations consistent
across the two builds.

Author: Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com>
Discussion: http://postgr.es/m/CAN4CZFP6NOjv__4Mx+iQD8StdpbHvzDAatEQn2n15UKJ=MySSQ@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/59dcc19b397f69a3654d39bae5a13f1659d922d8

Modified Files
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contrib/pg_plan_advice/Makefile | 2 ++
contrib/pg_plan_advice/meson.build | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)