pgsql: gen_guc_tables.pl: Improve detection of inconsistent data

gen_guc_tables.pl: Improve detection of inconsistent data

This commit adds two improvements to gen_guc_tables.pl:
1) When finding two entries with the same name, the script complained
about these being not in alphabetical order, which was confusing.
Duplicated entries are now reported as their own error.
2) While the presence of the required fields is checked for all the
parameters, the script did not perform any checks on the non-required
fields. A check is added to check that any field defined matches with
what can be accepted. Previously, a typo in the name of a required
field would cause the field to be reported as missing. Non-mandatory
fields would be silently ignored, which was problematic as we could lose
some information.

Author: Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com>
Reviewed-by: Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>
Reviewed-by: Michael Paquier <michael(at)paquier(dot)xyz>
Discussion: https://postgr.es/m/CAN4CZFP=3xUoXb9jpn5OWwicg+rbyrca8-tVmgJsQAa4+OExkw@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/233e6ae95330eac51880b050908b1e3ac9860d9b

Modified Files
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src/backend/utils/misc/gen_guc_tables.pl | 29 +++++++++++++++++++++++++++--
1 file changed, 27 insertions(+), 2 deletions(-)