Created Curl_raw_nequal() which does a C-locale string case comparison.

Changed checkprefix() to use it and those instances of strnequal() that
compare host names or other protocol strings that are defined to be
independent of case in the C locale.  This should fix a few more
Turkish locale problems.

lib/cookie.c

@@ -131,7 +131,7 @@ static bool tailmatch(const char *little, const char *bigone)
   if(littlelen > biglen)
     return FALSE;
 
-  return (bool)strequal(little, bigone+biglen-littlelen);
+  return (bool)Curl_raw_equal(little, bigone+biglen-littlelen);
 }
 
 /*