title: How to set up the PostgreSQL tutorial?
body: <p>I'm trying to follow the tutorial on PostgreSQL (<a href="https://www.postgresql.org/docs/9.5/static/tutorial-sql-intro.html" rel="nofollow noreferrer">https://www.postgresql.org/docs/9.5/static/tutorial-sql-intro.html</a>). I'm running version 9.5.7, so I downloaded the corresponding source code and tried</p>
  
  <pre><code>kurt@kurt-ThinkPad:~/Downloads/postgresql-9.5.7/src/tutorial$ make
  Makefile:27: /usr/lib/postgresql/9.5/lib/pgxs/src/makefiles/pgxs.mk: No such file or directory
  make: *** No rule to make target '/usr/lib/postgresql/9.5/lib/pgxs/src/makefiles/pgxs.mk'.  Stop.
  </code></pre>
  
  <p>However, it's not able to find certain <code>Makefile</code>s as shown in the error message above. Am I doing anything wrong?</p>