I have installed PostgreSQL 9.x and PostGIS 1.5/2.0 several times and have never had this problem.
I just got a new CentOS 6.3 server up and running and and I have Postgres 9.3 functioning as expected. I have run
yum install postgis2_93
and I can see the files in
/usr/pgsql-9.3/share/contrib/
however, when I run
CREATE EXTENSION postgis;
I receive
ERROR: could not open extension control file "/usr/pgsql-9.3/share/extension/postgis.control": No such file or directory
the tutorials (#1, #2) I have used don't show any steps between installing PostGIS and creating the extension.
What am I missing?
The postgis2_93 RPM provided by http://yum.pgrpms.org/ is missing extension support. I reported this to Devrim earlier this week and he has been attempting to fix it.
http://svn.pgrpms.org/changeset/299
Hopefully the next push of RPMS to the website resolves this.
Update: postgis2_93-2.1.0-3 was released, which solved this issue but placed a rpm requirement for gdal 1.9, which EPEL does not provide. I got it from ELGIS.