* guix-package.in (roll-back): Fix file name of PREVIOUS-PROFILE, which
  could end up containing the dirname twice.
  Reported by Nikita and Andreas.
* tests/guix-package.sh: Add test.

* distro.scm: Rename to...
* gnu/packages.scm: ... this.  Update all users accordingly.
* Makefile.am (MODULES): Adjust accordingly.
* po/POTFILES.in: Likewise.

* distro: Rename to...
* gnu: ... this.  Update module names accordingly.
* Makefile.am: Adjust accordingly.
* po/POTFILES.in: Likewise.
* distro.scm: Search for files under /gnu/packages instead of
  /distro/packages.
* gnu/packages/base.scm (ld-wrapper-boot3): Likewise.

* guix-package.in (profile-numbers): New procedure.
  (latest-profile-number): Use it.
  (previous-profile-number): New procedure.
  (roll-back): Use it lieu of `1-'.  Check whether PREVIOUS-NUMBER is
  zero, and raise an error when it is.
* tests/guix-package.sh: Test whether we can roll back over a "hole".

Based on a patch by Nikita Karetnikov <nikita@karetnikov.org>.

* guix-package.in (profile-regexp): New procedure.
  (latest-profile-number): Remove `%profile-rx', and use
  `profile-regexp' instead.
  (profile-number, roll-back): New procedure.
  (show-help): Add `--roll-back'.
  (%options): Likewise.
  (guix-package)[process-actions]: First check whether `roll-back?' is
  among OPTS, and call `roll-back' if it is, followed by a recursive
  call to `process-actions'.  Emit the "nothing to be done" message only
  when INSTALL or REMOVE is non-empty.
* tests/guix-package.sh (readlink_base): New function.
  Add tests for `--roll-back'.
* doc/guix.texi (Invoking guix-package): Document `--roll-back'.

* guix-package.in (%store): Change to a SRFI-39 parameter.  Update all users.
  (guix-package): Parametrize %STORE to an open connection after
  `parse-options' has been called.

Reported by Andreas Enge.

* guix-package.in (%profile-directory): Honor $NIX_STATE_DIR.
  (guix-package)[ensure-default-profile]: Use it.
  [process-actions]: Call it when the `profile' option is
  %CURRENT-PROFILE.
* tests/guix-package.sh: Add installation test with $HOME set, using the
  default profile.

* guix-package.in (guix-package): When testing whether
  %USER-ENVIRONMENT-DIRECTORY exists, use `lstat' instead of
  `file-exists?'.  Reported by Andreas Enge.

* guix-package.in (guix-package): Create the %USER-ENVIRONMENT-DIRECTORY
  symlink if it doesn't exist yet.
* doc/guix.texi (Invoking guix-package): Document it.

* guix-package.in (guix-package)[process-query]: For `list-available',
  show the outputs of each package.
* doc/guix.texi (Invoking guix-package): Update accordingly.

* guix-package.in (guix-package): Use either %BOOTSTRAP-GUILE or
  GUILE-FINAL.

* guix-package.in (guix-package)[guile-missing?]: New procedure.
  (guix-package): Always redirect `current-build-output-port' to
  `current-error-port' when (guile-missing?).

* guix-package.in (%options): Remove #\b as an alternate for
  "bootstrap".
  (show-help): Adjust accordingly.
* tests/guix-package.sh: Use `--bootstrap' instead of `-b'.

Change all license headers, except guix/build/* and ld-wrapper.scm, with
this code:

  (use-modules (guix build utils)
	       (srfi srfi-1))

  (fluid-set! %default-port-encoding "UTF-8")

  (substitute* (remove (lambda (f)
			 (or (string-contains f ".tar.")
			     (string-contains f ".git/")
			     (string-contains f ".so")
			     (string-suffix? ".o" f)
			     (string-suffix? ".a" f)
			     (string-suffix? ".go" f)
			     (string-suffix? ".pdf" f)
			     (string-suffix? ".png" f)
			     (string-suffix? ".info" f)
			     (equal? (basename f) "guix-daemon")
			     (equal? (basename f) "nix-setuid-helper")
			     (string-contains f "nix-upstream/")
			     (string-contains f "distro/packages/bootstrap/")))
		       (find-files "." "\\.[a-z]+$"))
    (("^([[:graph:]]+) This file is part of Guix." _ comment-start)
     (string-append comment-start " This file is part of GNU Guix."))
    (("^([[:graph:]]+) Guix --- Nix package management.*" _ comment-start)
     (string-append comment-start
		    " GNU Guix --- Functional package management for GNU\n"))
    (("^([[:graph:]]+) Guix is " _ comment-start)
     (string-append comment-start " GNU Guix is "))
    (("^([[:graph:]]+) along with Guix." _ comment-start)
     (string-append comment-start " along with GNU Guix."))
    (("^([[:graph:]]+) Copyright \\(C\\)" _ comment-start)
     (string-append comment-start " Copyright ©")))

Change headers using C-style comments manually.

* guix/config.scm.in (%guix-home-page-url): New variable.
* guix/ui.scm (show-bug-report-information): New procedure.
* guix-build.in (show-help): Use it.
* guix-download.in (show-help): Likewise.
* guix-import.in (show-help): Likewise.
* guix-package.in (show-help): Likewise.

* guix-package.in (%current-profile): Change to `guix-profile'.

* guix-package.in (%profile-directory): Use %STATE-DIRECTORY instead of
  a hard-coded directory.

* guix-package.in (%profile-directory): Use %STATE-DIRECTORY instead of
  a hard-coded directory.

* 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.

* 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.

* guix-package.in (guix-package)[process-actions]: Extract the version
  string from store paths.
* tests/guix-package.sh: Adjust accordingly.

* guix-package.in (guix-package)[find-package]: Return (package-version p),
  not VERSION.

* 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.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.

* guix-package.in (guix-package)[find-package]: Don't use `_' as the
  wildcard, to avoid collision with `gettext'.

* guix-package.in (guix-package)[find-package]: Return the correct NAME
  and SUB-DRV when NAME contains #\:.

* tests/guix-package.sh (profile): Add test.

* guix-package.in: Use (distro packages guile), not (... base).

* guix-package.in (_, N_): Remove.

* guix/utils.scm (package-name->name+version): New procedure.
* guix-package.in (guix-package)[find-package]: Use it.
* tests/utils.scm ("package-name->name+version"): New test.

* guix-package.in (leave): Remove.
  (guix-package): Wrap body in `with-error-handling'.

* guix/ui.scm (show-version-and-exit): New procedure.
* guix-build.in (show-version): Remove.
  (%options)["version"]: Use `show-version-and-exit'.
* guix-download.in: Likewise.
* guix-package.in: Likewise.

* guix-package.in, tests/guix-package.sh: New files.
* configure.ac: Output `guix-package'.
* Makefile.am (TESTS): Add `tests/guix-package.sh'.
  (bin_SCRIPTS): Add `guix-package'.