Fix pg_basebackup output to stdout on Windows.

Fix pg_basebackup output to stdout on Windows.

When writing a backup to stdout with pg_basebackup on Windows, put stdout
to binary mode. Any CR bytes in the output will otherwise be output
incorrectly as CR+LF.

In the passing, standardize on using "_setmode" instead of "setmode", for
the sake of consistency. They both do the same thing, but according to
MSDN documentation, setmode is deprecated.

Fixes bug #14634, reported by Henry Boehlert. Patch by Haribabu Kommi.
Backpatch to all supported versions.

Discussion: https://www.postgresql.org/message-id/20170428082818.24366.13134@wrigleys.postgresql.org