pgsql: Centralize resetting SIGCHLD handler

Centralize resetting SIGCHLD handler

All postmaster child processes reset SIGCHLD signal handler in their
respective Main functions. To avoid the duplication, do it earlier in
process startup, in InitPostmasterChild().

Reviewed-by: Andres Freund <andres(at)anarazel(dot)de>
Discussion: https://www.postgresql.org/message-id/b88a764a-b2e4-4dac-9d25-7249215db2b7@iki.fi

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2e2751e69760e66eadb2b6f0a2d084034ac8d597

Modified Files
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src/backend/postmaster/autovacuum.c | 2 --
src/backend/postmaster/bgworker.c | 1 -
src/backend/postmaster/bgwriter.c | 5 -----
src/backend/postmaster/checkpointer.c | 5 -----
src/backend/postmaster/pgarch.c | 3 ---
src/backend/postmaster/startup.c | 5 -----
src/backend/postmaster/syslogger.c | 5 -----
src/backend/postmaster/walsummarizer.c | 5 -----
src/backend/postmaster/walwriter.c | 5 -----
src/backend/replication/logical/slotsync.c | 1 -
src/backend/replication/walreceiver.c | 3 ---
src/backend/replication/walsender.c | 3 ---
src/backend/tcop/postgres.c | 7 -------
src/backend/utils/init/miscinit.c | 12 +++++++++++-
14 files changed, 11 insertions(+), 51 deletions(-)