title: PHP looking for ext folder on wrong drive
body: <p>I have installed PHP 7 on windows 10 to my <code>E:</code> drive so I can try out composer.</p>
  
  <p>When I try to run composer I get an error that it can't find the extensions I enabled but I can see it is looking in <code>C:\php\ext</code> and not <code>E:\php\ext</code>.</p>
  
  <p>I looked in <code>php.ini</code> but  couldn't see whre to set the path of the root installation.</p>
  
  <p>Does it always default to <code>C:</code>?  How do I tell it to look in <code>E:</code>?</p>