Minor PostgreSQL updates and different unpleasant surprises

Today I've updated two our DBMS servers to PostgreSQL 9.0.7. It was a minor update, everything went smoothly: I just updated ports and let pormaster to do its job...
But I got an interesting consequence - something was fixed and our server began to write error log in Russian. Oh, shit! It wasn't pleasant. Have you ever tried to find something about particular error using its localized description?
I've checked my environment: LC_* variables were not set, pgsql's user class was not "russian", nothing has changed. However, I got a nice log with localized reports... One more trouble - they were messed up in some way (don't know, whose fault was this - OS, PostgreSQL) and hardly readable. I really don't understand, why OS or any service should ever print any errors or logs in native language, this practice leads to difficulties in their interpretation.
In any way, it turned out that in postgresql.conf lc_messages were set to "ru_RU.UTF-8", maybe since initdb run, but before update this GUC didn't have such influence. Something was fixed, and behavior changed. So, keep in mind, even minor updates may lead to different surprises...