bug#32452: 26.1; gnutls_try_handshake maxes out cpu retrying when server is a bit busy

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@gmail.com>
> Cc: 32452@debbugs.gnu.org
> Date: Fri, 17 Aug 2018 18:10:32 -0400
> 
> The debbugs server seems back to normal speeds now, I'm getting ~200
> hits with it just like other servers.  The patch below brings it down to
> 15~20.

Good.

> nanosleep isn't portable though right?

We could use usleep instead, it's part of Posix, AFAIK.  And MinGW has
it as well, AFAICT.  Sorry I didn't mention it in the first place.

Thanks.