Comment 1 for bug 122183

I've been trying to figure out the problem.

I noticed that when the package builds, it creates directories for version 8.2 (!), but I only have 8.1 installed
<code>$ find install-8.1/
install-8.1/
install-8.1/usr
install-8.1/usr/lib
install-8.1/usr/lib/postgresql
install-8.1/usr/lib/postgresql/8.2
install-8.1/usr/lib/postgresql/8.2/lib
install-8.1/usr/lib/postgresql/8.2/lib/plr.so
install-8.1/usr/share
install-8.1/usr/share/doc
install-8.1/usr/share/doc/postgresql-doc-8.2
install-8.1/usr/share/doc/postgresql-doc-8.2/contrib
install-8.1/usr/share/doc/postgresql-doc-8.2/contrib/README.plr
install-8.1/usr/share/postgresql
install-8.1/usr/share/postgresql/8.2
install-8.1/usr/share/postgresql/8.2/contrib
install-8.1/usr/share/postgresql/8.2/contrib/plr.sql
</code>

I traced the "8.2" down to /usr/lib/postgresql/8.2/bin/pg_config which is part of the libpq-dev package. Seems like libpq-dev is only available in 8.2 for fiesty.
libpq-dev (>=8.1) is required by postgresql-server-dev-8.1, and postgresql-server-dev-8.1 is required when doing a "sudo apt-get build-dep postgresql-8.1-plr"

The permanent fix would be to make version 8.1 of libpg-dev available.

However, I have a patch which hard codes the paths. (See next comment for the fix)