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/ftp.c

@@ -4019,7 +4019,7 @@ CURLcode ftp_parse_url_path(struct connectdata *conn)
 
     dlen -= ftpc->file?strlen(ftpc->file):0;
     if((dlen == (int)strlen(ftpc->prevpath)) &&
-       curl_strnequal(path, ftpc->prevpath, dlen)) {
+       strnequal(path, ftpc->prevpath, dlen)) {
       infof(data, "Request has same path as previous transfer\n");
       ftpc->cwddone = TRUE;
     }