Introduce InvalidCommandId.

This allows a 32-bit field to represent an *optional* command ID
without a separate flag bit.

Andres Freund
Show schemas in information_schema.schemata that the current has access to

Before, it would only show schemas that the current user owns.  Per
discussion, the new behavior is more useful and consistent for PostgreSQL.
Remove leftover function prototype.

The prototype for inval_twophase_postcommit wasn't removed when it's definition
was removed in efc16ea520679d713d98a2c7bf1453c4ff7b91ec / the initial HS commit.

Andres Freund
psql: honor 'footer' option for expanded output

"No rows" previously only honored the tuples-only option.

Per report from Eli Mesika
psql: fix \copy stdin trailing space requirement

Previously a trailing space was required for \copy ... stdin:

	copy foo from stdin ;

Etsuro Fujita
Add comment for VARSIZE_ANY_EXHDR macro

Gurjeet Singh
docs:  Update libpq and testlo examples

Josh Kupershmidt
fuzzystrmatch: replace broken link in C comment

Albe Laurenz
merge compress_backup_block into full_page_writes
Merge branch 'master' into fpw-compress-dont-skip-hole