ERROR: must be superuser to alter superusers

Hi,

I had the very bad idea of removing the "superuser" flag from the
"pgsql" role. Now each time I try to set it back, with:

ALTER ROLE pgsql
SUPERUSER;

... I get:

ERROR: must be superuser to alter superusers
SQL state: 42501

Since there is no superuser in the database engine anymore, what option
do I have?

I tried:

CREATE ROLE pgsql2
SUPERUSER;

... But I get:

ERROR: must be superuser to create superusers
SQL state: 42501

Thanks,

Philippe Lang