GRANT ON C

I'm trying to load the pgcypto.sql file from the contrib in a database and
I've hit a problem which I never had in the past (maybe never did it this
way): when I try to load this file (psql -f) with a specific user, which is
not the postgres super-user I get a permission denied, and couldn't find how
to change that permission problem.
I the postgres super-user the only one that can create functions with LANGUAGE
C?

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select 'mmarques' || '@' || 'unl.edu.ar' AS email;
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Martín Marqués                  |        mmarques@unl.edu.ar
Programador, Administrador, DBA |       Centro de Telemática
                       Universidad Nacional
                            del Litoral
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