Merge branch 'master' into nix-integration

guix-build: Don't connect to the daemon when run with `--version' or `--help'.

* guix-build.in (%store): Turn into a SRFI-39 parameter.  Update users.
  (guix-build): Set %STORE and call `open-connection' only after
  `parse-options' has been called.

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.

Augment `TODO'.

distro: Add GNU lsh.

* distro/packages/lsh.scm,
  distro/packages/patches/lsh-guile-compat.patch:
  distro/packages/patches/lsh-no-root-login.patch:
  distro/packages/patches/lsh-pam-service-name.patch: New files.
* Makefile.am (MODULES): Add lsh.scm.
  (dist_patch_DATA): Add the above patches.

distro: Add util-linux.

* distro/packages/linux.scm (util-linux): New variable.

distro: Add psmisc.

* distro/packages/linux.scm (psmisc): New variable.

build: Add `bootstrap' and `sync-with-upstream' scripts.

* bootstrap, nix/sync-with-upstream: New files.
* Makefile.am (EXTRA_DIST): Add `bootstrap'.
* daemon.am (EXTRA_DIST): Add `nix/sync-with-upstream'.

build: Add Nix as a sub-module.

* .gitmodules, nix-upstream: New files.

build: Include a copy of Nix's libstore and daemon; build it.

* configure.ac: Call `AC_USE_SYSTEM_EXTENSIONS', and
  `GUIX_SYSTEM_TYPE'.  Add `--with-store-dir' option, and substitute
  `storedir'.  Include `config-daemon.ac'.
* config-daemon.ac: New file.
* Makefile.am [BUILD_DAEMON]: Include `daemon.am'.
* daemon.am: New file.
* m4/guix.m4 (GUIX_SYSTEM_TYPE): New macro.

* nix/libutil/gcrypt-hash.cc, nix/libutil/gcrypt-hash.hh,
  nix/libutil/md5.h, nix/libutil/sha1.h, nix/libutil/sha256.h,
  nix/nix-daemon/guix-daemon.cc, nix/nix-daemon/shared.hh: New files.

distro: make-bootstrap: Use `linux' module.

* distro/packages/make-bootstrap.scm: Use (distro packages linux).  This
  is a followup to 80fe5c6.

distro: gnutls: Build sequentially.

* distro/packages/gnutls.scm (gnutls)[arguments]: New field.

distro: guile-2.0: Update to 2.0.7.

* distro/packages/guile.scm (guile-2.0): Switch to 2.0.7.
  (guile-2.0/fixed): Stay at 2.0.6.

distro: Add `guile-2.0/fixed', which should rarely change.

* distro/packages/guile.scm (guile-2.0/fixed): New variable.
* distro/packages/base.scm (guile-final): Use it.

distro: Import 'gettext' under a different name.

* distro/packages/nano.scm, distro/packages/wget.scm: Import 'gettext'
  from (distro packages gettext) under 'guix:gettext'.

distro: linux-libre-headers: Move to (distro packages linux).

* distro/packages/base.scm (linux-libre-headers): Move to...
* distro/packages/linux.scm (linux-libre-headers): ... here.

distro: Add Linux-PAM.

* distro/packages/linux.scm: New file.
* Makefile.am (MODULES): Add it.

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.