[HACKERS] pg_upgrade and missing loadable libraries

I have seen a few reports where people are getting this pg_upgrade
error:
Your installation references loadable libraries that are missingfrom the new installation.  You can add these libraries
tothenew installation, or remove the functions using them from theold installation.  A list of problem libraries is in
thefile:    ./loadable_libraries.txt
 
and the file contains:
could not load library "$libdir/pgpool-regclass":ERROR:  could not access file "$libdir/pgpool-regclass": No such file
ordirectory
 

The problem is that there is no indicate of which database to look in. 
Should we adjust the output to suggest the first database that has it,
or update the instructions to mention they have to look in all
databases, and give them some instructions on finding the problem?

This seems to be one of the last pg_upgrade problems, along with
preserving optimizer statistics, which I am hoping to do for PG 11.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +