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.

tests: Remove `t-profile' files on exit.

* tests/guix-package.sh: Use a trap on EXIT to remove profile-related
  files.  Reported by Andreas Enge <andreas@enge.fr>.

guix-package: Gracefully handle multiple installs of the same path.

* guix-package.in (guix-package)[process-actions]: Compute PACKAGES such
  that packages listed in INSTALL* are first removed from the remainder
  of the list.  When PROF is equal to the previous profile's store path,
  do nothing.  Reported by Andreas Enge <andreas@enge.fr>.
* tests/guix-package.sh: Test the behavior of installing the same store
  path twice.  When removing a package, omit its version number.

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>.

distro: lout: Delay use of of `nixpkgs-derivation'.

* distro/packages/lout.scm (lout): Don't fork with `nixpkgs-derivation',
  to avoid any issues in the absence of `nix-instantiate'.

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.

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.

Update `THANKS'.

doc: Correct short name of `--install' option of `guix-package'.

* doc/guix.texi (Invoking guix-package): Fix short form of `--install'.
  Reported by Andreas Enge <andreas@enge.fr>.

Update `TODO'.

Change email address in `AUTHORS'.

Update `AUTHORS'.

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.

distro: Add ACL.

* distro/packages/acl.scm: New file.  Dependency on Perl added by
  Ludovic.
* Makefile.am (MODULES): Add it.

distro: Add Attr.

* distro/packages/attr.scm: New file.  Dependency on Perl and
  `patch-shebang' added by Ludovic.
* Makefile.am (MODULES): Add it.

Add (guix gnu-maintenance).

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

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.