download: Remove unreachable SourceForge mirror.

* guix/download.scm (%mirrors)[sourceforge]: Remove kent.dl.*, which is
  unreachable.

download: Correctly detect "No route to host" conditions.

* guix/build/download.scm (open-connection-for-uri): Delete addrinfos
  with the same address.  Always open SOCK_STREAM/IPPROTO_IP sockets.
  Fix the error handler's condition to determine what to do.
  Reported by Nikita Karetnikov <nikita.karetnikov@gmail.com> at
  <http://lists.gnu.org/archive/html/bug-guix/2012-12/msg00150.html>.

download: Work around (web client) bug <http://bugs.gnu.org/13095>.

* guix/build/download.scm: Annihilate `shutdown' in (web client).

build: Fix default value of `%state-directory'.

* guix/config.scm.in (%state-directory): Append `/nix'.
  Reported by Andreas Enge <andreas@enge.fr>.

Merge branch 'nix-integration'

Conflicts:
	tests/guix-package.sh

licenses: Add 'bsd-style', 'expat', 'gpl1', 'gpl1+', 'lgpl2.0', and 'lgpl2.0+'.

* guix/licenses.scm (bsd-style, expat, gpl1, gpl1+)
  (lgpl2.0, lgpl2.0+): New variables.

Have `%nixpkgs-directory' default to #f when $NIXPKGS is the empty string.

* guix/utils.scm (%nixpkgs-directory): Set to #f when the `NIXPKGS'
  environment variable is set but empty.  Reported by
  Andreas Enge <andreas@enge.fr>.

derivations: Distinguish direct store paths from files within a store path.

* guix/derivations.scm (derivation)[direct-store-path?]: New procedure.
  Use it to determine which inputs must be added to the store.

Merge branch 'master' into nix-integration

Conflicts:
	guix/store.scm

store: Add GC-related operations.

* guix/store.scm (gc-action): New enumerate type.
  (read-long-long, read-string-list, write-store-path,
  write-store-path-list, read-store-path-list): New procedures.
  (write-arg): Add support for `store-path' and `store-path-list'.
  (read-arg): Add support for `store-path-list'.
  (define-operation): Add support for multiple-value returns.
  (run-gc, live-paths, dead-paths, collect-garbage, delete-paths): New
  procedures.
  (%long-long-max): New macro.
* tests/store.scm: New file.
* Makefile.am (TESTS): Add it.

store: Add `add-temp-root'.

* guix/store.scm (add-temp-root): New procedure.

Add (guix licenses).

* guix/licenses.scm: New file.
* Makefile.am (MODULES): Add it.

download: Fix the primary Savannah URL.

* guix/download.scm (%mirrors)[savannah]: Use
  "http://download.savannah.gnu.org/releases/" as the primary URL.

build: Capture configure-time settings in (guix config).

* configure.ac: Compute and substitute `guix_localstatedir'.
* m4/guix.m4: Substitute `guix_system'.
* guix/config.scm.in (%store-directory, %store-directory, %system): New
  variables.
* guix/store.scm (%nix-state-dir): Remove.
  (%default-socket-path): Use %STATE-DIRECTORY as the default.
  (%store-prefix): Use %STORE-DIRECTORY as the default.
* guix/utils.scm (%current-system): Default to %SYSTEM.

Add (guix gnu-maintenance).

* guix/gnu-maintenance.scm: New file.
* Makefile.am (MODULES): Add it.

Merge branch 'master' into nix-integration

store: Honor $NIX_STORE_DIR and $NIX_STATE_DIR.

* guix/store.scm (%nix-state-dir): Honor $NIX_STATE_DIR.
  (%store-prefix): Honor $NIX_STORE_DIR.

derivations: Fix erroneous call to `add-to-store' for local files as input.

* guix/derivations.scm (derivation)[inputs]: Fix typo in call to
  `add-to-store'.
* tests/derivations.scm ("derivation with local file as input"): New test.
* tests/packages.scm ("trivial with local file as input"): New test.

download: Add kernel.org mirrors.

* guix/download.scm (%mirrors): Add `kernel.org' mirrors.

download: Keep only one slash when concatenating URIs.

* guix/build/download.scm (url-fetch)[uri-vicinity]: New procedure.
  [maybe-expand-mirrors]: Use it.