[quake3] Curl download support

[Tony J. White]

On Thu, Nov 09, 2006 at 05:16:17PM +0100, Thilo Schulz wrote:
> I've got around testing curl support and my compliments to tjw: this stuff 
> seems to work excellently.
> One minor issue:
> Can't you make quake3 use UDP download as fallback if downloading via URL 
> gives an error like 404?

I have considered it, but this will not work when "disconnected download"
is set since by the time we find out about a cURL error, the client has
already dropped the connection.

So in the current implementation, the only case when we can fall back to
UDP on a cURL error is when:

1) sv_allowDownload is set to allow both UDP and cURL
2) cl_allowDownload is set to allow both UDP and cURL
3) sv_allowDownload is set to NOT disconnect on cURL download

I assume most server admins making use of the cURL downloads will use
disconnected download mode.  (At least they do in ET)

IMO it would be better to boldy display a cURL error if there
is one so the server admin becomes aware of it.  If we just print a
warning to console and fall back to UDP, it might cause some confusion
for the server admin when people complain that the server is slow instead
of giving the admin a descriptive message.

-Tony