gnu: guile-ncurses: Update to 1.6.

* gnu/packages/guile.scm (guile-ncurses): Update to 1.6.

build: Adjust lint tests for latest rules.

* tests/guix-lint.sh (dummy)[description]: Add failing case.
  [doc]: Adjust.

list-packages: Add Hydra links only for the supported systems.

* build-aux/list-packages.scm (package->sxml)[status]: Use
  'package-transitive-supported-systems' instead of a hard-coded list of
  systems.

gnu: mit-scheme: Fix typo in 'supported-systems'.

* gnu/packages/scheme.scm (mit-scheme)[supported-systems]: Correct
  spelling of "mips64el-linux".

gnu: atlas: Make it non-substitutable.

Suggested by Federico Beffa <beffa@ieee.org>.

* gnu/packages/maths.scm (atlas)[arguments]: Pass #:substitutable? #f.
  [description]: Adjust accordingly.

build-system/gnu: Add #:substitutable? parameter.

* guix/build-system/gnu.scm (gnu-build): Add #:substitutable?
  parameter.  Pass #:local-build? to 'build-expression->derivation'.
  (gnu-cross-build): Likewise.

gnu: Mark a few packages as unsupported on MIPS.

* gnu/packages/gprolog.scm (gprolog): Add 'supported-systems' field.
* gnu/packages/qemu.scm (qemu-headless): Likewise.
* gnu/packages/qt.scm (qt): Likewise.
* gnu/packages/scheme.scm (racket): Likewise.

emacs: Add 'guix-pull' command.

* emacs/guix-base.el (guix-pull): New command.
  (guix-update-after-pull, guix-after-pull-hook): New variables.
  (guix-restart-repl-after-pull, guix-update-buffers-maybe-after-pull): New
  procedures.
* emacs/guix-main.scm: Use (guix scripts pull) module.
* doc/emacs.texi (Emacs Commands): Document 'guix-pull' command.

emacs: Improve REPL procedures.

* emacs/guix-backend.el (guix-start-process-maybe): Add 'start-msg' and
  'end-msg' optional arguments.
  (guix-start-repl-maybe): Likewise.  Do not kill buffer with a dead process.
  (guix-repl-exit): New procedure.
  (guix-eval-in-repl): Use 'geiser-repl--send'.

emacs: Improve buffer procedures.

* emacs/guix-base.el (guix-list-or-info-buffer-p): Delete.  Replace with...
  (guix-buffer-p): ... this.  New procedure.
  (guix-buffers): Use it.  Add 'modes' argument.
  (guix-update-buffer): New procedure.
  (guix-update-buffers-maybe): Rename to ...
  (guix-update-buffers-maybe-after-operation): this.  Use
  'guix-update-buffer'.

emacs: Introduce REPL operation type.

* emacs/guix-backend.el (guix-repl-operation-type): New variable.
  (guix-repl-output-filter): Run type hooks after performing an operation.
  (guix-eval-read): Add 'operation-type' argument.

emacs: Handle updating by ID after REPL restart.

* emacs/guix-base.el (guix-entry-to-specification,
  guix-entries-to-specifications): New procedures.
  (guix-revert-buffer): Search by name if searching by ID gives no results.

doc: Add a note about optional GnuTLS dependency.

* README (Requirements): add a note about 'guix download''s GnuTLS dependency.
* doc/guix.texi (Requirements): Likewise.

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

doc: Add cross-reference to the gnutls-guile manual.

* doc/guix.texi (Invoking guix download): Add cross-reference to the
  gnutls-guile manual.

gnu: Add miscfiles

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

gnu: Add prefix to license imports in (gnu packages feh).

* gnu/packages/feh.scm: Import (guix licenses) with #:prefix license: to avoid
  importing 'imlib2' from both (gnu packages image) and (guix licenses).

gnu: ruby: Miscellaneous improvements to package definition.

* gnu/packages/ruby.scm (ruby): Compute major+minor version string for the
  source URI.  Switch to the .bz2 tarball and update the hash accordingly.
  Remove 'autoconf' from the inputs.  Change 'native-search-paths' to the
  directory that is actually created by the build.  Remove the package name
  from the synopsis.
  (ruby-1.8): Compute major+minor version string for the source URI, and avoid
  the use of 'name' in the URI computation.  Remove 'name' field, since it is
  inherited and no longer needed.

gnu: Add ruby 1.8.7.

* gnu/packages/ruby.scm (ruby-1.8): New variable.

gnu: gnutls: Fix path to a guile site directory.

Suggested by Ludovic Courtès.

* gnu/packages/gnutls.scm (gnutls): Add '--with-guile-site-dir' configure
  flag.

gnu: parallel: Update to 20141022.

* gnu/packages/parallel.scm (parallel): Update to 20141022.