pgbench: Silence compiler warning

Explicitly ignore return value from write(), to silence warning.  This
warning only appeared under --disable-thread-safety.
Fix include-guard

Looks like a cut/paste error in the original addition of the file.

Andres Freund
pg_upgrade:  document link options
Document that tablespaces and pg_xlog can be on different file systems
for pg_upgrade --link mode.
Backpatch to 9.3.
pg_resetxlog: Make --help consistent with man page

Use "MXID" as placeholder for -m option, instead of just "XID".
pg_isready: Make --help output more consistent with other utilities
Fix planning of parameterized appendrel paths with expensive join quals.

The code in set_append_rel_pathlist() for building parameterized paths
for append relations (inheritance and UNION ALL combinations) supposed
that the cheapest regular path for a child relation would still be cheapest
when reparameterized.  Which might not be the case, particularly if the
added join conditions are expensive to compute, as in a recent example from
Jeff Janes.  Fix it to compare child path costs *after* reparameterizing.
We can short-circuit that if the cheapest pre-existing path is already
parameterized correctly, which seems likely to be true often enough to be
worth checking for.

Back-patch to 9.2 where parameterized paths were introduced.