BUG #6318: pg_dump for non-template languages is broken

The following bug has been logged on the website:

Bug reference: 6318
Logged by: Laurenz Albe
Email address: laurenz(dot)albe(at)wien(dot)gv(dot)at
PostgreSQL version: 9.1.1
Operating system: Linux (RHEL 3)
Description:

How to reproduce:

postgres=# CREATE DATABASE dumpme;
postgres=# \c dumpme postgres
dumpme=# CREATE LANGUAGE mylang HANDLER plpgsql_call_handler INLINE
plpgsql_inline_handler VALIDATOR plpgsql_validator;
dumpme=# \q

$ pg_dump -C -F p -f dumpme.sql dumpme

$ psql -c 'DROP DATABASE dumpme'

$ psql -f dumpme.sql
[...]
psql:dumpme.sql:32: ERROR: unsupported language "mylang"
HINT: The supported languages are listed in the pg_pltemplate system
catalog.
psql:dumpme.sql:35: ERROR: language "mylang" does not exist
[...]

The reason is that the dump contains:

--
-- Name: mylang; Type: PROCEDURAL LANGUAGE; Schema: -; Owner: advpg
--

CREATE OR REPLACE PROCEDURAL LANGUAGE mylang;

ALTER PROCEDURAL LANGUAGE mylang OWNER TO advpg;

Yours,
Laurenz Albe