pgsql: Fix tar files emitted by pg_basebackup to be POSIX conformant.

Fix tar files emitted by pg_basebackup to be POSIX conformant.

Back-patch portions of commit 05b555d12bc2ad0d581f48a12b45174db41dc10d.
There doesn't seem to be any reason not to fix pg_basebackup fully, but
we can't change pg_dump's "magic" string without breaking older versions
of pg_restore. Instead, just patch pg_restore to accept either version
of the magic string, in hopes of avoiding compatibility problems when
9.3 comes out. I also fixed pg_dump to write the correct 2-block EOF
marker, since that won't create a compatibility problem with pg_restore
and it could help with some versions of tar.

Brian Weaver and Tom Lane

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/900d77fa57565ac5881acf464e76a88069605ad2

Modified Files
--------------
doc/src/sgml/protocol.sgml | 8 +++--
src/backend/replication/basebackup.c | 63 +++++++++++++++++++++------------
src/bin/pg_dump/pg_backup_tar.c | 27 ++++++++++----
3 files changed, 64 insertions(+), 34 deletions(-)