pgsql: Remove lc_ctype_is_c().

Remove lc_ctype_is_c().

Instead always fetch the locale and look at the ctype_is_c field.

hba.c relies on regexes working for the C locale without needing
catalog access, which worked before due to a special case for
C_COLLATION_OID in lc_ctype_is_c(). Move the special case to
pg_set_regex_collation() now that lc_ctype_is_c() is gone.

Author: Andreas Karlsson
Discussion: https://postgr.es/m/60929555-4709-40a7-b136-bcb44cff5a3c@proxel.se

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/51edc4ca54f826cfac012c7306eee479f07a5dc7

Modified Files
--------------
src/backend/regex/regc_pg_locale.c | 21 ++++++++++++++++++---
src/backend/utils/adt/formatting.c | 27 ++++++++++++---------------
src/backend/utils/adt/like.c | 2 +-
src/backend/utils/adt/like_support.c | 19 +++++++------------
src/backend/utils/adt/pg_locale.c | 26 --------------------------
src/include/catalog/pg_collation.dat | 3 +--
src/include/utils/pg_locale.h | 2 --
7 files changed, 39 insertions(+), 61 deletions(-)