pg_dumpall fails if a database name contains =

~/pgsql.92stable$ bin/createdb "foo=bar"
~/pgsql.92stable$ bin/pg_dumpall > /dev/null
pg_dump: [archiver (db)] connection to database "(null)" failed: invalid
connection option "foo"
pg_dumpall: pg_dump failed on database "foo=bar", exiting

There are two bugs above:

1. When pg_dumpall passes the database name to pg_dump as a command line
argument, pg_dump interprets it as a connection string if it contains =.

2. When you pass an invalid connection string to pg_dump, it passes a
NULL pointer to printf when constructing the error message. It shows as
"(null)" above, but would segfault on other platforms.

- Heikki