title: What is the correct path for the '--with-mysql=DIR' option for configuring PHP
body: <p>I am trying to compile PHP from source with the MySQL extension as a shared library. The instructions provided by <code>./configure --help</code> say:</p>
  
  <pre><code>--with-mysql=DIR      Include MySQL support.  DIR is the MySQL base directory.
  </code></pre>
  
  <p>However, I have no idea what they mean by MySQL base directory! Is this the directory where the mysql client executable is? (e.g. on my machine /usr/bin). Or do they mean where the shared libraries (i.e. libmysqlclient.so and libmysqlclient_r.so) are located (e.g. on my machine /usr/lib)? Or some other place? I have tried several locations, but still when I try to use the compiled version of php I get the errors like:</p>
  
  <pre><code>Call to undefined function mysql_connect()
  </code></pre>
  
  <p>Please help! Thanks in advance.</p>