Add feature to install q3c extension in RDS PostgreSQL via pg_tle

## Describe the problem

* What are you trying to solve?
I'm trying to install the q3c exntesion in RDS Aurora PostgreSQL using pg_tle, but it gives me the following error.

test => CREATE EXTENSION q3c;
ERROR: permission denied for language c

## Describe the proposal

* What is the feature you are proposing?
Add feature to support language c to install q3c extension.

* How would it solve the problem?
It helps the astronomical community where q3c extension is being mainly used for Spatial Index queries.

## Describe alternatives

* How would you solve the problem today if the feature is not built?
PostGIS is the alternative in RDS for q3c.

* What other alternatives are there?
PostGIS is the alternative in RDS for q3c.