pgsql: Add some const qualifiers

Add some const qualifiers

There was a mismatch between the const qualifiers for
excludeDirContents in src/backend/backup/basebackup.c and
src/bin/pg_rewind/filemap.c, which led to a quick search for similar
cases. We should make excludeDirContents match, but the rest of the
changes seem like a good idea as well.

Author: David Steele <david(at)pgmasters(dot)net>
Discussion: https://www.postgresql.org/message-id/flat/669a035c-d23d-2f38-7ff0-0cb93e01d610(at)pgmasters(dot)net

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/64b787656de6c0c6f8f2e6e5b8a3cea25b92458b

Modified Files
--------------
contrib/fuzzystrmatch/fuzzystrmatch.c | 2 +-
contrib/pgcrypto/pgp-armor.c | 4 ++--
src/backend/catalog/heap.c | 2 +-
src/backend/utils/adt/ruleutils.c | 4 ++--
src/backend/utils/misc/guc.c | 4 ++--
src/bin/initdb/initdb.c | 4 ++--
src/bin/pg_amcheck/pg_amcheck.c | 2 +-
src/bin/pg_rewind/filemap.c | 2 +-
src/bin/pg_rewind/parsexlog.c | 2 +-
src/bin/pgbench/pgbench.c | 4 ++--
src/interfaces/libpq/pqexpbuffer.c | 2 +-
11 files changed, 16 insertions(+), 16 deletions(-)