pgsql: ssl: Remove static var tracking tls_init_hook warnings

ssl: Remove static var tracking tls_init_hook warnings

If the TLS init hook is defined in conjunction with ssl_sni we
issue a warning to help the user re-configure the cluster. To
avoid drowning the log in warnings, we log only once instead of
once per host. This removes the static variable tracking the
warning to aid future multithreading efforts.

Author: Daniel Gustafsson <daniel(at)yesql(dot)se>
Reviewed-by: Tristan Partin <tristan(at)partin(dot)io>
Reviewed-by: Andreas Karlsson <andreas(at)proxel(dot)se>
Reviewed-by: Yilin Zhang <jiezhilove(at)126(dot)com>
Discussion: https://postgr.es/m/68B9881D-DAA8-467D-A251-C96E98E57BA0@yesql.se

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/9e526a14d7cb36c24d6faebf32df31251a97edc9

Modified Files
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src/backend/libpq/be-secure-openssl.c | 29 ++++++++++++++++++++++-------
1 file changed, 22 insertions(+), 7 deletions(-)