pgsql: Prevent running pg_basebackup as root

Prevent running pg_basebackup as root

Similarly to pg_upgrade, pg_ctl and initdb, a root user is able to use
--version and --help, but cannot execute the actual operation to avoid
the creation of files with permissions incompatible with the
postmaster.

This is a behavior change, so not back-patching is done.

Author: Ian Barwick
Discussion: https://postgr.es/m/CABvVfJVqOdD2neLkYdygdOHvbWz_5K_iWiqY+psMfA=FeAa3qQ@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/7bae0ad9fcb76b28410571dc71edfdc3175c4a02

Modified Files
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src/bin/pg_basebackup/pg_basebackup.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)