Add `guix-gc'.

* guix-gc.in, tests/guix-gc.sh: New files.
* configure.ac: Output `guix-gc', and make it executable.
* Makefile.am (bin_SCRIPTS): Add `guix-gc'.
  (TESTS): Add `tests/guix-gc.sh'.
* doc/guix.texi (Features): Add xref to "Invoking guix-gc".
  (Invoking guix-gc): New node.
* po/POTFILES.in: Add `guix-gc.in'.

guix-build: Add `--verbosity'.

* guix-build.in (%default-options): Add `verbosity'.
  (%options): Add `--verbosity'.
  (guix-build): Pass it to `set-build-options'.
  (show-help): Update accordingly.
* doc/guix.texi (Invoking guix-build): Document `--verbosity'.

guix-package: Add `--verbose'; silence the environment's build by default.

* guix-package.in (%options): Add `--verbose'.
  (show-help): Update accordingly.
  (guix-package): Parameterize `current-build-output-port' according to
  VERBOSE?.  By default, silence the environment build's output.

doc: Fix typos.

* doc/guix.texi: Fix typos.  Reported by Andreas Enge <andreas@enge.fr>.

Merge branch 'master' into nix-integration

Conflicts:
	guix/store.scm

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>.

doc: Mention the pronunciation of "Guix".

* README: Mention pronunciation of "Guix".
* doc/guix.texi (Introduction): Likewise.

doc: Document basic package definitions.

* doc/guix.texi (Programming Interface): Add introduction.
  (Defining Packages): Populate.

guix-package: Add `--list-available'.

* guix-package.in (show-help, %options): Add `--list-available'.
  (guix-package)[process-query]: Add support for `--list-available'.
* doc/guix.texi (Invoking guix-package): Document it.
* tests/guix-package.sh: Add test.

* guix/ui.scm (location->string): New procedure.
* guix/utils.scm: Export <location>.

guix-package: Add `--list-installed'.

* guix-package.in (show-help, %options): Add `--list-installed'.
  (guix-package): Move main body to...
  [process-actions]: ... here.  New internal procedure.
  [process-query]: New procedure.
* tests/guix-package.sh: Add tests for `--list-installed'.
* doc/guix.texi (Invoking guix-package): Document it.

Turn Guix into "GNU Guix".

* configure.ac: Change package name to "GNU Guix", and bug-report
  address to `gnu-system-discuss@gnu.org'.
* doc/guix.texi: Replace "Guix" by "GNU Guix" in some places.
  (Top, Introduction): Mention "for the GNU system".
* HACKING, README: Use "GNU Guix" instead of "Guix" in some places.

doc: Document the features and `guix-package'.

* doc/guix.texi: Change the category to "Package management".  Add an
  @direntry for "Invoking guix-package".
  (Package Management): New chapter.

doc: Document `guix-build'.

* doc/guix.texi (Invoking guix-build): Populate.

doc: Remove unnecessary @ifinfo.

* doc/guix.texi: Remove @ifinfo around @dir{category,entry}.  Suggested
  by Karl Berry <karl@freefriends.org>.

doc: Add the stub of a manual.

* doc/guix.texi: New file.
* doc/fdl-1.3.texi: New file, copied from Gnulib.

* Makefile.am (info_TEXINFOS): New variable.
  (EXTRA_DIST): Add `doc/fdl-1.3.texi'.