Extensions support for pg_dump, patch v27

Hi,

Following recent commit of the hstore Makefile cleaning, that I included
into my extension patch too, I have a nice occasion to push version 27
of the patch.  Please find it enclosed.  This time I'm not including the
contrib-only and doc-src split versions, just ask for them if that's
what you need.

Of course you can also use my git repository:

  http://git.postgresql.org/gitweb?p=postgresql-extension.git;a=shortlog;h=refs/heads/extension

Regards,
-- 
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support