we can compare if non-NULL elsewhere

if a connection is tunneled through a proxy. A tunnel is done with CONNECT,
either when using HTTPS or FTPS, or if explicitly enabled by the app.

idea (not really new, but its better to have it mentioned in here)

both with older libidn versions without idn_free() and with libidn versions
that gets installed without idn-free.h

versions

interface is used

the curl_easy_strerror() function to provide one

 Gisle's previous mail. We now use this function, and thus we require libidn
 0.4.5 or later. No earler version will do.

not be used both in one request. Fixed it and added test case 172 to verify.

set to the domain .a.b.c (that is with a dot prefix). This is now fixed and
test case 171 verifies it.

once and for all