store: Make '%store-monad' an alias for '%state-monad'.

* guix/store.scm (define-alias): New macro.
  (%store-monad, store-return, store-bind): Define as aliases of the
  corresponding %STATE-MONAD part.
  (store-lift, text-file, interned-file): Return STORE as a second
  value.
  (run-with-store): Use 'run-with-state'.
* guix/packages.scm (set-guile-for-build, package-file): Return STORE as
  a second value.
* guix/monads.scm: Remove part of the module commentary.

monads: Add the state monad.

* guix/monads.scm (state-return, state-bind, run-with-state,
  current-state, set-current-state, state-push, state-pop): New
  procedures.
  (%state-monad): New variable.
* tests/monads.scm (%monads): Add %STATE-MONAD.
  (%monad-run): Add 'run-with-state'.
  (values->list): New macro.
  ("set-current-state", "state-push etc."): New tests.

gnu: linux-libre: Update to 3.18.3

* gnu/packages/linux.scm (linux-libre): Update to version 3.18.3.

gnu: rasqal: Update to 0.9.33.

* gnu/packages/rdf.scm (rasqal): Update to 0.9.33.

gnu: raptor2: Update to 2.0.15.

* gnu/packages/rdf.scm (raptor2): Update to 2.0.15.

guix archive: Add -r/--recursive.

* guix/scripts/archive.scm (show-help, %options): Add -r/--recursive.
  (export-from-store): Pass #:recursive? to 'export-paths'.
* doc/guix.texi (Invoking guix archive): Add -r in Emacs example.  Add
  example with ~/.guix-profile.  Document -r/--recursive.

guix archive: Remove unused -r/--root option.

* guix/scripts/archive.scm (%options): Remove -r/--root.

store: Remove unused variable.

* guix/store.scm (export-paths): Remove unused variable 's'.

store: Add #:recursive? parameter to 'export-paths'.

* guix/store.scm (export-paths): Add #:recursive? parameter and honor
  it.
* tests/store.scm ("export/import incomplete", "export/import
  recursive"): New tests.

doc: Mention generation of ECDSA/Ed25519 keys when supported.

* doc/guix.texi (Invoking guix archive): Mention ECDSA/Ed25519 as the
  default type of keys for libgcrypt >= 1.6.0.

gnu: Add fvwm.

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

gnu: fontconfig: Propagate expat and freetype.

* gnu/packages/fontutils.scm (fontconfig)[inputs]: Move expat and freetype ...
  [propagated-inputs]: ... to here.

gnu: ffmpeg: Augment rpath of libraries.

* gnu/packages/video.scm (ffmpeg)[arguments]<phases>[add-lib-to-run-path]:
  Add $out/lib to the RUNPATH of libraries.

gnu: fontconfig: Update to 2.11.92.

* gnu/packages/fontutils.scm (fontconfig): Update to 2.11.92.

emacs: In 'run-with-store' call, specify the guile-for-build.

This fixes a regression introduced in commit e87f059.

* emacs/guix-main.scm (process-package-actions): Add call to
  'set-guile-for-build' in monadic expression.

gnu: e2fsck-static: Use really statically-linked executables.

* gnu/packages/linux.scm (e2fsprogs/static): New variable.
  (e2fsck/static): Use it in 'inputs'.

gnu: Add CGAL.

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

system: Add "en_US.UTF-8" to the default locales, for backward compatibility.

* gnu/system/locale.scm (%default-locale-definitions): Add
  "en_US.UTF-8".

gnu: Add Eigen.

* gnu/packages/algebra.scm (eigen): New variable.

gnu: Add IPython.

* gnu/packages/python.scm (python-ipython, python2-ipython): New variable.