title: PHP setlocale() not working for ctype_alpha check
body: <p>I run this php code:</p>
  
  <pre><code>echo "&lt;br&gt;system locales: ".system('locale -a')."&lt;br&gt;&lt;br&gt;";
  echo "current locales: ".setlocale(LC_ALL, 0)."&lt;br&gt;&lt;br&gt;";
  var_dump(setlocale (LC_ALL, 'de_DE.utf8'));
  echo "current locales: ".setlocale(LC_ALL, 0)."&lt;br&gt;&lt;br&gt;";
  echo "accepting german characters?: ".ctype_alpha("äüöß")."&lt;br&gt;&lt;br&gt;";
  echo "accepting characters in general?: ".ctype_alpha("test")."&lt;br&gt;&lt;br&gt;";
  echo "rejecting numbers?: ".ctype_alpha("tes2t")."&lt;br&gt;&lt;br&gt;";
  </code></pre>
  
  <p>and get this output:</p>
  
  <pre><code>C C.UTF-8 POSIX de_DE.utf8
  system locales: de_DE.utf8
  
  current locales: C
  
  string(10) "de_DE.utf8" current locales: de_DE.utf8
  
  accepting german characters?:
  
  accepting characters in general?: 1
  
  rejecting numbers?
  </code></pre>
  
  <p>I expected that after the call to setlocale (LC_ALL, 'de_DE.utf8') ctype_alpha would accept german characters like äöüß, as written in the documentation: <a href="http://www.php.net/manual/en/function.ctype-alpha.php" rel="nofollow">"Returns TRUE if every character in text is a letter from the <strong>current locale</strong>, FALSE otherwise."</a> but it doesn't. 
  What am i doing wrong here?</p>
  
  <p>PHP Version  is : 5.3.10-1ubuntu3.8</p>