pg_dumpall --exclude-database case folding

[discussion transferred from psql-performance]

Summary: pg_dumpall and pg_dump fold non-quoted commandline patterns to
lower case

Tom lane writes:

Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> On 6/10/21 2:23 PM, Andrew Dunstan wrote:
>> Ouch. That looks like a plain old bug. Let's fix it. IIRC I just used
>> the same logic that we use for pg_dump's --exclude-* options, so we need
>> to check if they have similar issues.

> Peter Eisentraut has pointed out to me that this is documented, albeit a
> bit obscurely for pg_dumpall. But it is visible on the pg_dump page.

Hmm.

> Nevertheless, it's a bit of a POLA violation as we've seen above, and
> I'd like to get it fixed, if there's agreement, both for this pg_dumpall
> option and for pg_dump's pattern matching options.

+1, but the -performance list isn't really where to hold that discussion.
Please start a thread on -hackers.

regards, tom lane