BUG #13481: No config folder upon installation

The following bug has been logged on the website:

Bug reference:      13481
Logged by:          Bailu Ding
Email address:      bailuding@gmail.com
PostgreSQL version: 9.5alpha1
Operating system:   Ubuntu 14.04
Description:

I compiled the source code following the instructions in the INSTALL file.
After the installation, the directory sysconfdir was not created. I tried
both using the default configuration (where the sysconfdir should be
/usr/local/pgsql/etc/) and specifying the sysconfdir variable explicitly.

I am able to run the database and to run queries successfully. But where
should I look for the config files?

Best,
Bailu