src/pl/plperl/README

PL/Perl allows you to write PostgreSQL functions and procedures in
Perl.  To include PL/Perl in the build use './configure --with-perl'.
To build from this directory use 'make all; make install'.  libperl
must have been built as a shared library, which is usually not the
case in standard installations.

Consult the PostgreSQL User's Guide and the INSTALL file in the
top-level directory of the source distribution for more information.