hydra: Update Guix job set.

* build-aux/hydra/guix.scm (tarball-package): Remove 'nix-checkout'
  parameter.  Remove 'arguments', 'native-inputs', and 'location'
  fields.  Adjust caller accordingly.
  (hydra-jobs): Remove 'nix-checkout'.

build-system/gnu: 'dist-package' preserves the package's native inputs.

* guix/build-system/gnu.scm (dist-package)[native-inputs]: Preserve P's
  native-inputs.

build-system/gnu: Adjust to removal of a "bin" output for Libtool.

* guix/build-system/gnu.scm (dist-package): Change libtool:bin input to
  just libtool.

gnu: linux-libre: Update to 4.0.1.

* gnu/packages/linux.scm (linux-libre): Update to 4.0.1.

gnu: ebook: Drop circular inclusion of the module into itself.

* gnu/packages/ebook.scm: Do not import (gnu packages ebook).

services: Add console-keymap service.

* gnu/services/base.scm (console-keymap-service): New procedure.
* doc/guix.texi (Base Services): Document it.

Co-authored-by: 宋文武 <iyzsong@gmail.com>

serialization: Adjust the permissive UTF-8 decoder to Guile 2.0.12ish.

* guix/serialization.scm (read-maybe-utf8-string): Use
  'set-port-encoding!' and 'set-port-conversion-strategy!' instead of
  setting '%default-port-encoding' and
  '%default-port-conversion-strategy'.  This accounts for Guile commit
  d574d96, which changes bytevector input ports to use ISO-8859-1.

substitute: Fix file descriptor leak in 'http-multiple-get'.

In practice we would not leak much since we reconnect after ~100
requests (with nginx running on hydra.gnu.org.)

* guix/scripts/substitute.scm (http-multiple-get): Call 'close-port'
  before 'connect'.

Thank Joshua.

download: Honor the 'http_proxy' and 'https_proxy' env. vars.

Fixes <http://bugs.gnu.org/20402>.
Reported by Joshua Randall <jcrandall@alum.mit.edu>.

* guix/download.scm (url-fetch): Pass #:leaked-env-vars to
  'gexp->derivation'.

derivations: Add #:leaked-env-vars parameter.

Suggested by Joshua Randall <jcrandall@alum.mit.edu>
in <http://bugs.gnu.org/20402>.

* guix/derivations.scm (derivation): Add #:leaked-env-vars parameter.
  [user+system-env-vars]: Honor it.
* guix/gexp.scm (gexp->derivation): Add #:leaked-env-vars and pass it to
  'raw-derivation'.
* doc/guix.texi (Derivations, G-Expressions): Adjust accordingly.

download: Simplify 'open-connection-for-uri' to support HTTP proxies.

Partly fixes <http://bugs.gnu.org/20402>.
Reported by Joshua Randall <jcrandall@alum.mit.edu>.

* guix/build/download.scm (open-connection-for-uri): Rewrite to be a
  small wrapper around 'open-socket-for-uri'.  This procedure was
  initially introduced in d14ecda to work around the lack of NSS modules
  during bootstrap but that has become unnecessary since 0621349, which
  introduced a bootstrap Guile that uses static NSS modules (from commit
  d3b5972.)
  On Guile >= 2.0.10, this allows the 'http_proxy' environment variable
  to be used.

gnu: Add orcus.

* gnu/packages/libreoffice.scm (orcus): New variable.

gnu: libva: Patch a dlopen call, set drivers path.

* gnu/packages/video.scm (libva): Patch the reference to libva-x11.so (passed
  to dlopen()) to use an absolute path.  Add --with-drivers-path= to
  #:configure-flags with a value pointing to mesa's $prefix/lib/dri.

install: Make /var/lock.

Reported by 宋文武 <iyzsong@gmail.com>.

* gnu/build/install.scm (directives): Add /var/lock.

gnu: Remove gstreamer-0.10 and gst-plugins-base-0.10.

* gnu/packages/gstreamer.scm (gstreamer-0.10, gst-plugins-base-0.10):
  Remove variables.
* gnu/packages/patches/gstreamer-0.10-bison3.patch,
  gnu/packages/patches/gstreamer-0.10-silly-test.patch: Remove files.
* gnu-system.am (dist_patch_DATA): Remove them.

gnu: Add xmp.

* gnu/packages/audio.scm (xmp): New variable.

gnu: Add libxmp.

* gnu/packages/audio.scm (libxmp): New variable.

gnu: Add libmodplug.

* gnu/packages/audio.scm (libmodplug): New variable.

gnu: Add python-tornado.

* gnu/packages/python.scm (python-tornado, python2-tornado): New variables.