[pgpool-committers: 5922] pgpool: Use pg_get_expr() instead of pg_attrdef.adsrc to support for Po

[Bo Peng]

Use pg_get_expr() instead of pg_attrdef.adsrc to support for PostgreSQL 12.

Since PostgreSQL 12 removed pg_attrdef.adsrc, use pg_get_expr() instead of pg_attrdef.adsrc if the backend version is 7.3 or later.

Thanks to Takuma Hoshiai for creating the patch.

Branch
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V4_0_STABLE

Details
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https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=717411fd74a11cc839f81d70de37cc890309f45c

Modified Files
--------------
src/include/protocol/protocol_defs.h | 12 ++++++--
src/protocol/pool_process_query.c    | 12 ++++++--
src/rewrite/pool_timestamp.c         | 54 ++++++++++++++++++++++++++++++++----
3 files changed, 66 insertions(+), 12 deletions(-)