Hi,

Changes since the v1:

 * Simplification: keep-lingering? has been removed.  For
   tests/challenge, I have taken the proposed with-http-server*,
   renamed it to with-http-server/monadic to avoid confusion and
   removed its hardcoding of ports.

 * Simplification: the semantics of with-http-server*/with-http-server
   are now a bit simpler: it _always_ chooses a fresh port, regardless
   of whether %http-server-port was already set.

 * Simplification: %local-url and %local-url* have been unified to a
   single one-optional-argument procedure.

 * Simplification: no tests use %http-server-port anymore.  Instead,
   they directly use %local-url.  

 * YMMV: %http-server-port is now a lexical variable instead of a dynamic
   parameter, using syntax parameters.

 * The ‘home-page: Connection refused’ test does not hardcode 9999 anymore.
   Instead, 'with-unreachable-http-server' binds a fresh port (claiming it)
   but does not listen to it (causing connections to be refused).

 * Simplification: with-http-server only supports a single form now:
   a list of (uri response-code response) triples.  The URI must now
   always be set!  Existing tests have been adjusted appropriately.

What would be preferred:

 * The 2827e9f8a5834be65f8709a595ec2d870fd39271 commit from https://notabug.org/maximed/scheme-gnunet/
   (https://notabug.org/maximed/guix-gnunet/commit/2827e9f8a5834be65f8709a595ec2d870fd39271)
 * or a bunch of v2 mails sent with "git send-email?

Greetings,
Maxime.