title: Case insensitive std::string.find()
body: <p>I am using <code>std::string</code>'s <code>find()</code> method to test if a string is a substring of another. Now I need case insensitive version of the same thing. For string comparison I can always turn to <code>stricmp()</code> but there doesn't seem to be a <code>stristr()</code>.</p>
  
  <p>I have found various answers and most suggest using <code>Boost</code> which is not an option in my case.  Additionally, I need to support <code>std::wstring</code>/<code>wchar_t</code>. Any ideas?</p>