title: How to force QLocale::system to change
body: <p>I need to test my application translation to non-English language very often, and this is very uncomfortable to change the whole operating system language just to do this simple check.
  How can i change Qt-detected system language using environment variables for example?
  or with command-line parameter.</p>
  
  <p>I try to change <code>LANG</code>, <code>LANGUAGE</code> environment variables, but it has no effect.
  However, under GNOME it has!</p>
  
  <p>UPD: code i'm using such code to determine the system locale and load appropriate translation:</p>
  
  <pre><code>QTranslator app_translator;
  if (!app_translator.load ("app_" + QLocale::system ().name (), app_tr_dir))
      qWarning ("Can't load app translator file for locale %s from %s", qPrintable (QLocale::system ().name ()), app_tr_dir.toLocal8Bit().data());
  else
      app.installTranslator (&amp;app_translator);
  </code></pre>
  
  <p>P.S. My OS is Kubuntu 13.10, Qt version is 4.8.</p>