[HACKERS] Adding -E switch to pg_dumpall

Hi all,

While looking at a user problem, I got surprised that pg_dumpall does
not have a -E switch. This has been discussed a bit in the past like
here:
https://www.postgresql.org/message-id/75E4C42D37E6A74E9FB57C2E9F1300D60107073E@tiger.nexperience.com

Now it is possible to enforce the encoding used by using
PGCLIENTENCODING but I think that a switch would be useful as well,
particularly for Windows where "set" needs to be used. Are there any
objections to a patch adding support for that? Such a patch should do:
- Call PQsetClientEncoding if an encoding is defined after getting a connection.
- Pass down -E to pg_dump calls if something is set.

Thoughts?
-- 
Michael