gnu: Add mpc123.

* gnu/packages/mp3.scm (libmpcdec, mpc123): New variables.

gnu: Changes references to (gnu packages admin).

* gnu/packages/version-control.scm, gnu/packages/vim.scm,
  gnu/system.scm, gnu/system/dmd.scm, gnu/system/shadow.scm,
  gnu/system/vm.scm: Change references to (gnu packages system) to (gnu
  packages admin).
  This is a followup to commit 4aeea89.

gnu: Rename (gnu packages system) to (gnu packages admin).

* gnu/packages/system.scm: Rename to...
* gnu/packages/admin.scm: ... this.  Adjust module name accordingly.
* gnu-system.am (GNU_SYSTEM_MODULES): Update.

gnu: Add ISC's DHCP implementation.

* gnu/packages/system.scm (isc-dhcp): New variable.

gnu: Add libtirpc.

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

guix package: Gracefully handle EPIPE on '--search'.

* guix/scripts/package.scm (guix-package): Wrap body of 'search' in
  'leave-on-EPIPE'.

ui: Don't use hyphens in 'package->recutils' output.

* guix/ui.scm (package->recutils): Rename recutils field from
  'home-page' to 'homepage'.

gnu: Add aumix.

* gnu/packages/linux.scm (aumix): New variable.

gnu: Add GnuPG's pinentry.

* gnu/packages/gnupg.scm (pinentry): New variable.

gnu: guile-ssh: Remove now unneeded cruft.

* gnu/packages/ssh.scm (guile-ssh): Remove libssh version hack from
  'autoreconf' phase.

gnu: Add Aspell dictionaries.

* gnu/packages/aspell.scm (aspell-dictionary): New procedure.
  (aspell-dict-en, aspell-dict-eo, aspell-dict-es, aspell-dict-fr): New
  variables.

config: '%store-directory' always honors $NIX_STORE_DIR.

* guix/config.scm.in (%store-directory): Honor $NIX_STORE_DIR.
* guix/store.scm (%store-prefix): Use %store-directory directly.

config: '%state-directory' always honors $NIX_STATE_DIR.

* guix/config.scm.in (%state-directory): Honor $NIX_STATE_DIR.
* guix/scripts/package.scm (%profile-directory): Use %state-directory
  directly.
* guix/store.scm (%default-socket-path, log-file): Likewise.

store: Fix 'log-file' to support uncompressed logs.

* guix/store.scm (log-file): Report the file without '.bz2' if it
  exists.

archive: Add '--missing'.

* guix/scripts/archive.scm (show-help, %options): Add '--missing'.
  (guix-archive)[lines]: New procedure.
  Use it to honor '--missing'.
* tests/guix-archive.sh: Add tests.
* doc/guix.texi (Invoking guix archive): Document '--missing'.

gnu: lsh: Move generic patching to 'snippet'.

* gnu/packages/lsh.scm (lsh): Move generic patching to the 'snippet'
  field of 'origin'.

archive: Make sure $sysconfdir/guix exists.

* guix/pki.scm (ensure-acl): Make sure the directory of %ACL-FILE
  exists.
* guix/scripts/archive.scm (generate-key-pair): Likewise for
  %PUBLIC-KEY-FILE.

guix build: Add '--no-build-hook'.

* guix/scripts/build.scm (%default-options): Add 'build-hook?' pair.
  (show-help, %options): Add --no-build-hook.
  (guix-build): Pass the 'build-hook?' value to 'set-build-options'.
* doc/guix.texi (Invoking guix build): Document '--no-build-hook'.

guix package: Gracefully deal with EPIPE on stdout for --list-*.

* guix/scripts/package.scm (leave-on-EPIPE): New macro.
  (guix-package): Use it for 'list-installed', 'list-available', and
  '--list-generations'.
* tests/guix-package.sh: Add test.

gnu: lsh: Fix the absolute file name of 'sexp-conv'.

* gnu/packages/lsh.scm (lsh): Rename 'fix-test-suite' phase to
  'pre-configure'.  Set PATH_SEXP_CONV in environ.h.in.