gnu: dnsmasq: Update to 2.76 [fixes CVE-2015-3294].

* gnu/packages/dns.scm (dnsmasq): Update to 2.76.

gnu: ruby-mime-types: Update to 3.1.

* gnu/packages/ruby.scm (ruby-mime-types): Update to 3.1.
[native-inputs]: Add 'ruby-minitest-hooks'.

gnu: Add ruby-minitest-hooks.

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

gnu: Add ruby-sequel.

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

gnu: ruby-nokogumbo: Update to 1.4.7-1.

* gnu/packages/ruby.scm (ruby-nokogumbo): Update to 1.4.7-1.

gnu: ruby-mini-portile-2: Update to 2.1.0.

* gnu/packages/ruby.scm (ruby-mini-portile-2): Update to 2.1.0.

gnu: ruby-mime-types-data: Update to 3.2016.0221.

* gnu/packages/ruby.scm (ruby-mime-types-data): Update to 3.2016.0221.

gnu: ruby-shoulda-matchers: Update to 3.1.1.

* gnu/packages/ruby.scm (ruby-shoulda-matchers): Update to 3.1.1.
[arguments]: Remove 'fix-import' phase.

gnu: ruby-domain-name: Update to 0.5.20160310.

* gnu/packages/ruby.scm (ruby-domain-name): Update to 0.5.20160310.

gnu: ruby-nokogiri: Update to 1.6.7.2.

* gnu/packages/ruby.scm (ruby-nokogiri): Update to 1.6.7.2.
[arguments]: Relax 'mini_portile2' dependency.

guix: ruby-build-system: Extract gemspec during 'extract-gemspec'.

* guix/build/ruby-build-system.scm (build): Move extraction from here ...
(extract-gemspec): ... to here.  New variable.
(first-gemspec): New variable.
(%standard-phases): Add 'extract-gemspec' phase.

gnu: linux-libre: Update to 4.6.

* gnu/packages/linux.scm (linux-libre): Update to 4.6.
* gnu/packages/linux-libre-4.6-x86_64.conf,
gnu/packages/linux-libre-4.6-i686.conf: New files.
* gnu/packages/linux-libre-4.5-x86_64.conf,
gnu/packages/linux-libre-4.5-i686.conf: Delete files.
* Makefile.am (KCONFIGS): Update accordingly.

gnu: python-libxml2: Drop replacement from inherited libxml2.

This is a followup to commit 493e9a5a8f613764cfa396c33ee6cb381b0dbbef.

* gnu/packages/xml.scm (python-libxml2)[replacement]: Set to #f, overriding
inherited value.

gnu: freeipmi: Update to 1.5.2.

* gnu/packages/freeipmi.scm (freeipmi): Update to 1.5.2.

gnu: linux-libre-4.1: Update to 4.1.25.

* gnu/packages/linux.scm (linux-libre-4.1): Update to 4.1.25.

gnu: webkitgtk: Update to 2.12.3 [fixes CVE-2016-{1856,1857}].

* gnu/packages/webkit.scm (webkitgtk): Update to 2.12.3.

graft: Fail when one of the threads raises an exception.

Fixes <http://bugs.gnu.org/23581>.

* guix/build/graft.scm (exit-on-exception): New procedure.
(rewrite-directory): Use it to wrap REWRITE-LEAF.

size: Pass 'requisites' a list of items.

* guix/scripts/size.scm (substitutable-requisites): Change 'item' to
'items' and adjust.
(requisites*): Likewise.
(mappend-map): Remove.
(store-profile): Adjust accordingly.

store: 'requisites' now takes a list of store items.

* guix/store.scm (fold-path): Change 'path' to 'paths' and adjust body
accordingly.
(requisites): Likewise.
* guix/scripts/environment.scm (inputs->requisites): Adjust
user accordingly.
* guix/scripts/size.scm (requisites*): Likewise.
* guix/scripts/gc.scm (guix-gc): Likewise.
* tests/store.scm ("requisites"): Likewise.

size: Accept several arguments.

* guix/scripts/size.scm (display-profile): Display WHOLE at then end.
(guix-size): Accept several FILES.
* doc/guix.texi (Invoking guix size): Add example with several items.