gnu: libmicrohttpd: Update to 0.9.34.

* gnu/packages/gnunet.scm (libmicrohttpd): Update to 0.9.34.

Update SRFI-64 to the latest upstream version.

* srfi/srfi-64.scm: Export 'test-group'.  Call 'cond-expand-provide'.
* srfi/srfi-64.upstream.scm: Update to the latest upstream version.

gnu: Add miniupnpc.

* gnu/packages/upnp.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

Signed-off-by: Andreas Enge <andreas@enge.fr>

derivations: Remove unused 'derivation' parameter.

* guix/derivations.scm (derivation): Remove unused #:hash-mode parameter.
* doc/guix.texi (Derivations): Adjust accordingly.

gnu: Add libwebsockets.

* gnu/packages/libwebsockets.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

Add (guix git-download).

* guix/git-download.scm, guix/build/git.scm: New files.
* Makefile.am (MODULES): Add them.
* guix/packages.scm (<origin>): Fix comment for 'method' field.

doc: More on what's special about the archive format.

* doc/guix.texi (Invoking guix archive): Expound on what sets the Nar
  format apart.

nar: Produce archives with files sorted in C collation order.

* guix/nar.scm (write-file) <directory>: Pass 'string<?' as the second
  argument to 'scandir'.
* tests/nar.scm ("write-file puts file in C locale collation order"):
  New test.

derivations: Add support for recursive fixed-output derivations.

* guix/derivations.scm (<derivation-output>): Add 'recursive?' field.
  Adjust 'make-derivation-output' callers.
  (%read-derivation) <fixed-output>: When HASH-ALGO starts with 'r:',
  set the 'recursive?' field and drop 'r:' from the hash algo name.
  (write-derivation)[write-output]: Write the algo as 'r:HASH-ALGO' when
  the RECURSIVE? field is set.
  (derivation-hash) <fixed-output>: Prepend "r:" when RECURSIVE? is set.
  (fixed-output-path): New procedure.
  (derivation): Add #:recursive? parameter.  Use 'fixed-output-path' to
  compute the output file name of a fixed output derivation.
  (build-expression->derivation): Add #:recursive? parameter.  Pass it
  to 'derivation'.
* tests/derivations.scm ("fixed-output derivation, recursive",
  "build-expression->derivation produces recursive fixed-output",
  "build-expression->derivation uses recursive fixed-output"): New
  tests.
* doc/guix.texi (Derivations): Document #:recursive? for 'derivation'.
  Add #:recursive? for 'build-expression->derivation'.

guix hash: Add '--recursive'.

* guix/scripts/hash.scm (show-help): Add --recursive.
  (%options): Likewise.
  (guix-hash)[file-hash]: New procedure.  Honor --recursive.
  Use it.
* guix/nar.scm (write-file): Add missing field to the &nar-error
  condition raised upon unsupported file type; change its message to be
  more descriptive.
* tests/guix-hash.sh: Add tests with -r.
* doc/guix.texi (Invoking guix hash): Document --recursive.

ui: Handle SRFI-35 '&message' conditions.

* guix/ui.scm (call-with-error-handling): Add case for
  'message-condition?'.
* po/Makevars: Fix typo in comment.

nar: 'write-file' can write to non-file ports.

* guix/nar.scm (write-contents): Use 'sendfile' only when P is a file
  port.
* tests/nar.scm ("write-file supports non-file output ports"): New test.

gnu: mpc123: Add patch that fixes a segfault.

* gnu/packages/patches/mpc123-initialize-ao.patch: New file.
* gnu/packages/mp3.scm (mpc123): Use it.
* gnu-system.am (dist_patch_DATA): Add it.

gnu: emacs: Add more inputs: giflib, libice, libsm, alsa-lib.

* gnu/packages/emacs.scm (emacs): Add 'giflib', 'libice', 'libsm', and
  'alsa-lib' inputs.  Remove "--with-gif=no" from configure arguments.

gnu: Add giflib.

* gnu/packages/giflib.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

gnu: gmime: Use gnome mirror for download.

* gnu/packages/mail.scm (gmime): Use gnome mirror, fixes download problems
    with automatic https redirection.

gnu: hurd: Add MiG.

* gnu/packages/hurd.scm (mig): New variable.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

guix hash: Don't load the whole file in memory.

* guix/scripts/hash.scm (guix-hash)[eof->null]: Remove.
  (guix-hash): Use 'port-sha256' to compute the hash instead of
  'get-bytevector-all' and co.

gnu: tor: Upgrade to 0.2.4.20.

* gnu/packages/tor.scm (tor): Upgrade to 0.2.4.20.

gnu: Add gmime.

* gnu/packages/mail.scm (gmime): New variable.