gnu: gdbm: Upgrade to 1.11.

* gnu/packages/gdbm.scm (gdbm): Upgrade to 1.11.

build: Improve documentation of Nix-related options.

* configure.ac: Add documentation for --with-nix and --with-nixpkgs.

gnu: games: New module

* gnu/packages/games.scm (gnubik): New variable

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu: gnome: Add new package gtkglext

* gnu/packages/gnome.scm (gtkglext): New variable.
* gnu/packages/patches/gtkglext-disable-disable-deprecated.patch,
  gnu/packages/patches/gtkglext-remove-pangox-dependency.patch: New
  files.
* gnu-system.am (dist_patch_DATA): Add them.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

authenticate: Disallow imports signed with unauthorized keys.

* guix/scripts/authenticate.scm (signature-sexp): Remove.
  (guix-authenticate): Upon '-verify', check whether the signature's
  public key passes 'authorized-key?'.

Add (guix pki).

* guix/pki.scm, tests/pki.scm: New files.
* Makefile.am (MODULES): Add 'guix/pki.scm'.
  (SCM_TESTS): Add 'tests/pki.scm'.

config: Export '%config-directory'.

* configure.ac: Define and substitute 'guix_sysconfdir'.
* guix/config.scm.in (%config-directory): New variable.

Move 'with-atomic-file-output' to (guix utils).

* guix/scripts/substitute-binary.scm (with-atomic-file-output): Move to...
* guix/utils.scm (with-atomic-file-output): ... here.

pk-crypto: Add canonical-sexp to sexp conversion procedures.

* guix/pk-crypto.scm (canonical-sexp-fold, canonical-sexp->sexp,
  sexp->canonical-sexp): New procedures.
* tests/pk-crypto.scm ("canonical-sexp->sexp",
  "sexp->canonical-sexp->sexp"): New tests.

pk-crypto: Add 'canonical-sexp-length' and related procedures.

* guix/pk-crypto.scm (canonical-sexp-length, canonical-sexp-null?,
  canonical-sexp-list?): New procedures.
* tests/pk-crypto.scm ("canonical-sexp-length", "canonical-sexp-list?"):
  New tests.

pk-crypto: 'canonical-sexp-nth-data' returns a symbol for "tokens".

* guix/pk-crypto.scm (token-string?): New procedure.
  (canonical-sexp-nth-data): Return a symbol when the element is a
  "token", and a bytevector otherwise.
  (latin1-string->bytevector): Remove.
  (hash-data->bytevector): Adjust accordingly.
* tests/pk-crypto.scm ("canonical-sexp-nth"): Adjust accordingly.  Add
  octet string example.

authenticate: Store the public key as part of the signature.

* guix/scripts/authenticate.scm (signature-sexp): New procedure.
  (guix-authenticate): Use it to produce the signature.  Adjust
  verification code accordingly.
* tests/store.scm ("import corrupt path"): Adjust test accordingly.

pk-crypto: Rename 'gcry-sexp' to 'canonical-sexp'.

* guix/pk-crypto.scm: Rename procedures, variables, etc. from
  'gcry-sexp' to 'canonical-sexp'.  Add comment with references.
* guix/scripts/authenticate.scm, tests/pk-crypto.scm: Adjust
  accordingly.

gnu: python: Update to 3.3.3.

* gnu/packages/python.scm (python): Update to 3.3.3.

gnu: python-2: Update to 2.7.6.

* gnu/packages/python.scm (python-2): Update to 2.7.6.

gnu: parallel: Update to 20131122.

* gnu/packages/parallel.scm (parallel): Update to 20131122.

gnu: xorriso: Update to 1.3.4.

* gnu/packages/cdrom.scm (xorriso): Update to 1.3.4.

gnu: libcdio: Update to 0.92.

* gnu/packages/cdrom.scm (libcdio): Update to 0.92.

gnu: libextractor: Update to 1.3.

* gnu/packages/gnunet.scm (libextractor): Update to 1.3.

gnu: vim: Update to 7.4.

* gnu/packages/vim.scm (vim): Update to 7.4.