Re: psql: add \create_function command

walther@technowledgy.de writes:
> Pavel Stehule:
>> looks a little bit obscure - why do you need to do it from psql? And how 
>> frequently do you do it?

> I store all my SQL code in git and use "psql -e" to "bundle" it into an 
> extension, which is then deployed to production.

> The code is spread over many files, which include other files via \ir. 

That reminds me: if we do either \file_read or :{file}, we should
define relative paths as working like \ir, that is it's relative
to the current script's directory when we're reading from a script.
This is almost always the behavior you want, and the principal
functional problem with the `cat ...` solution is that it doesn't
work that way.

            regards, tom lane