bug#56005: [bug#56867] [PATCH] download: Do not wrap TLS port on GnuTLS >= 3.7.7.

[Thiago Jung Bauermann via Bug reports for GNU Guix <bug-guix@gnu.org>]

Hello Ludo,

I don't have any comment/insight on what you're doing in general, except
about one of your points below:

Ludovic Courtès <ludo@gnu.org> writes:

> First, I noticed that GnuTLS doesn’t implement ‘write_wait_fd’, only
> ‘read_wait_fd’ (not sure how problematic that is):
>
> scheme@(guile-user)> ,use(web client)
> scheme@(guile-user)> (define p (open-socket-for-uri "https://guix.gnu.org"))
> scheme@(guile-user)> ((@@ (ice-9 suspendable-ports) wait-for-writable) p)
> ice-9/boot-9.scm:1685:16: In procedure raise-exception:
> In procedure write_wait_fd: unimplemented
>
> Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
> scheme@(guile-user) [1]> ,q
> scheme@(guile-user)> ,use(gnutls)
> scheme@(guile-user)> (gnutls-version)
> $1 = "3.7.7"
> scheme@(guile-user)> ((@@ (ice-9 suspendable-ports) wait-for-readable) p)
> $2 = 1

This occasionally causes problems when fetching substitutes, as can be
seen in bug #56005 (during substitution: write_wait_fd: unimplemented).

-- 
Thanks
Thiago