Installing plpython3u

Hello,

I'm having problems installing plpython3u, this is my situation:
I have installed postgresql-9.3.5 in my home directory, from source. I used
(from my memory, it might not be exact)

./configure --prefix=$HOME;
make;
make install

Now I need to upload a database which requires plpython3u, and this is what
happens:

pg_restore -U berald01 -d sblab -h localhost -1 current_pg_sblab.backup.tar

pg_restore: [archiver (db)] Error while PROCESSING TOC:
pg_restore: [archiver (db)] Error from TOC entry 1590; 2612 24721
PROCEDURAL LANGUAGE plpython3u dberaldi
pg_restore: [archiver (db)] could not execute query: ERROR: could not
access file "$libdir/plpython3": No such file or directory
Command was: CREATE OR REPLACE PROCEDURAL LANGUAGE plpython3u;

If I try to create plpython3u I get:

createlang plpython3u sblab
createlang: language installation failed: ERROR: could not open extension
control file
"/data/sblab-home/berald01/share/postgresql/extension/plpython3u.control":
No such file or directory

I'm a bit at a loss, how do I add plpython3u?

My OS is CentOS release 6.

Thanks!
Dario