/usr/lib/ is in postgresql-server-dev-8.4 8.4.11-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/postgresql/
/usr/lib/postgresql/8.4/
/usr/lib/postgresql/8.4/bin/
/usr/lib/postgresql/8.4/bin/pg_config
/usr/lib/postgresql/8.4/lib/
/usr/lib/postgresql/8.4/lib/pgxs/
/usr/lib/postgresql/8.4/lib/pgxs/src/
/usr/lib/postgresql/8.4/lib/pgxs/src/Makefile.global
/usr/lib/postgresql/8.4/lib/pgxs/src/nls-global.mk
/usr/lib/postgresql/8.4/lib/pgxs/src/Makefile.port
/usr/lib/postgresql/8.4/lib/pgxs/src/makefiles/
/usr/lib/postgresql/8.4/lib/pgxs/src/makefiles/pgxs.mk
/usr/lib/postgresql/8.4/lib/pgxs/src/test/
/usr/lib/postgresql/8.4/lib/pgxs/src/test/regress/
/usr/lib/postgresql/8.4/lib/pgxs/src/test/regress/pg_regress
/usr/lib/postgresql/8.4/lib/pgxs/src/Makefile.shlib
/usr/lib/postgresql/8.4/lib/pgxs/config/
/usr/lib/postgresql/8.4/lib/pgxs/config/mkinstalldirs
/usr/lib/postgresql/8.4/lib/pgxs/config/install-sh