The following bug has been logged on the website:
Bug reference: 7548
Logged by: Reinhard Max
Email address: max(at)suse(dot)de
PostgreSQL version: 9.1.5
Operating system: openSUSE
Description:
It looks like the attempt to remove pg_upgrade's dependency on pg_config
(http://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=2815574) was
incomplete, since contrib/pg_upgrade/exec.c still contains the line
validate_exec(cluster->bindir, "pg_config");
which makes pg_upgrade refuse to run when pg_config can't be found.