pgsql: Add missing header declarations for pg_basebackup and pg_{dump,r

Add missing header declarations for pg_basebackup and pg_{dump,restore}

This fixes two compilation failures caused by 6f164e6. Interesting to
see that missing <limits.h> dies not fail in Linux or even Windows. On
MacOS, it fails, though.

Per various buildfarm members.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bc0cc68f8a1648029424e9300b2e4457acd474a6

Modified Files
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src/bin/pg_basebackup/pg_basebackup.c | 1 +
src/bin/pg_dump/parallel.h | 2 ++
2 files changed, 3 insertions(+)