gnu: Add sawfish.

* gnu/packages/sawfish.scm (sawfish): New variable.

gnu: Add rep-gtk.

* gnu/packages/sawfish.scm (rep-gtk): New variable.

gnu: Add librep.

* gnu/packages/sawfish.scm: New file.
* gnu/packages/patches/librep-rules.mk.patch: New file.
* gnu-system.am: Add them.

gnu: Add python-urwid and python2-urwid.

Based on preliminary work by Omar Radwan <toxemicsquire4@gmail.com>.

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

gnu: httpd: Add perl input.

* gnu/packages/web.scm (httpd): Add perl input.

gnu: inkscape: Update to 0.91.

* gnu/packages/inkscape.scm (inkscape): Update to 0.91.

gnu: node: Update to 0.10.36.

* gnu/packages/node.scm (node): Update to 0.10.36.

gnu: elfutils: Update to 0.161.

* gnu/packages/elf.scm (elfutils): Update to 0.161.

gnu: sipwitch: Update to 1.9.6.

* gnu/packages/telephony.scm (sipwitch): Update to 1.9.6.

Set Emacs indentation for `wrap-program'.

* .dir-locals.el (scheme-mode): Set `scheme-indent-function' of `wrap-program'
  to 1.

gnu: ucommon: Update to 6.3.0.

* gnu/packages/telephony.scm (ucommon): Update to 6.3.0.

Revert "gnu: python-matplotlib: Remove python-pillow input."

python-pillow is now fixed, so we can add it back.
This reverts commit dfbc33dceb803a3d54840613b08dc98f7be75f60.

gnu: openjpeg: Upgrade to 2.1.0.

* gnu/packages/image.scm (openjpeg): Upgrade to 2.1.0.
  (openjpeg-2.0): New variable.
* gnu/packages/pdf.scm (mupdf)[inputs]: Use openjpeg-2.0.

gnu: Add hdparm.

* gnu/packages/linux.scm (hdparm): New variable.

store: Remove 'build-derivations'.

* guix/store.scm (build-derivations): Remove.
* guix/derivations.scm (build-derivations): Write in terms of
  'build-things'.
* doc/guix.texi (Invoking guix build): Adjust text accordingly.

tests: Skip 'guix-register' when the socket name length is exceeded.

* tests/guix-register.sh: Before running 'guix-daemon', check whether
  the socket name length exceeds the system limitation.

tests: Don't dump the list of dead items in the test log.

* tests/store.scm ("dead-paths"): Wrap result in '->bool'.

store: Add 'build-things'.

* guix/store.scm (operation-id): Rename 'build-derivations' to
  'build-things', as per Nix commit 1aba0bf0.
  (build-derivations): Rename to...
  (build-things): ... this.  Keep 'build-derivations' as an alias.
  (build): New procedure.
* tests/store.scm ("build-things with output path",
  "substitute + build-things with output path"): New tests.

tests: Add 'with-derivation-substitute' and use it.

* guix/tests.scm (%substitute-directory): New variable.
  (call-with-derivation-narinfo): Use it.
  (call-with-derivation-substitute): New procedure.
  (with-derivation-substitute): New macro.
* tests/store.scm ("substitute"): Use 'with-derivation-substitute'.
  ("substitute, corrupt output hash"): Likewise.

tests: Further factorize substitute mocks.

* guix/tests.scm (derivation-narinfo): Turn 'nar' into a keyword
  parameter.  Add #:sha256 parameter, and honor it.
  (call-with-derivation-narinfo): Add #:sha256 and pass it to
  'derivation-narinfo'.
  (with-derivation-narinfo): Extend with support for (sha256 => value).
* tests/store.scm ("substitute query"): Use 'with-derivation-narinfo'.
  ("substitute"): Likewise.
  ("substitute, corrupt output hash"): Likewise.
  ("substitute --fallback"): Likewise.
* tests/derivations.scm: Remove Emacs local variable.