ui: Add a 'define-diagnostic' macro.

* guix/ui.scm (define-diagnostic): New macro, which is based on the
  previous version of 'warning'.
  (warning, leave): Redefine using 'define-diagnostic'.
  (report-error): New macro.
  (install-locale): Use 'warning' instead of 'format'.
  (call-with-error-handling): Adjust 'leave'.
* gnu/packages.scm (package-files): Use 'warning' instead of 'format'.
* guix/gnu-maintenance.scm (http-fetch): Use 'warning' and 'leave'.
* guix/scripts/build.scm (derivations-from-package-expressions, guix-build):
  Adjust 'leave'.
* guix/scripts/download.scm (guix-download): Adjust 'leave'.
* guix/scripts/gc.scm (size->number, %options): Adjust 'leave'.
* guix/scripts/package.scm (roll-back, guix-package): Adjust 'leave'.
* po/POTFILES.in: Add 'guix/gnu-maintenance.scm'.

scripts: Report what will be substituted.

* guix/derivations.scm (derivation-input-output-paths): New procedure.
  (derivation-prerequisites-to-build): New `use-substitutes?' keyword
  argument.  Change two return the list of substitutable paths as a
  second argument.
* guix/ui.scm (show-what-to-build): Turn `dry-run?' into a keyword
  argument.  New `use-substitutes?' keyword argument.  Use `fold2' and
  adjust to use both return values of
  `derivation-prerequisites-to-build'.  Display what will/would be
  downloaded.
* guix/scripts/build.scm (guix-build): Adjust accordingly.
* guix/scripts/package.scm (guix-package): Likewise.
* tests/derivations.scm ("derivation-prerequisites-to-build and
  substitutes"): New test.

ui: Add a `warning' macro.

* guix/ui.scm (program-name, guix-warning-port): New variables.
  (warning): New macro.
  (guix-main): Parametrize PROGRAM-NAME.
* guix/scripts/build.scm, guix/scripts/download.scm,
  guix/scripts/gc.scm, guix/scripts/package.scm: Adjust to use `leave'
  and `warning' consistently.

ui: Factorize `read/eval-package-expression'.

* guix/scripts/package.scm (read/eval-package-expression): Move to...
* guix/ui.scm (read/eval-package-expression): ... here.
* guix/scripts/build.scm (derivations-from-package-expressions): Use it.

ui: Factorize `show-what-to-build'.

* guix/scripts/package.scm (guix-package)[show-what-to-build]: Move to..
* guix/ui.scm (show-what-to-build): ... here.  Add a `store'
  parameter'.  Adjust callers.
* guix/scripts/build.scm (guix-build): Use it.  Remove `req' and `req*'
  variables.

scripts: Remove hyphen in the command name shown by `--version'.

* guix/scripts/build.scm (%options): Remove hyphen from the name passed
  to `show-version-and-exit'.
* guix/scripts/download.scm (%options): Likewise.
* guix/scripts/gc.scm (%options): Likewise.
* guix/scripts/import.scm (%options): Likewise.
* guix/scripts/package.scm (%options): Likewise.

scripts: Remove initialization now redundant with `initialize-guix'.

* guix/scripts/build.scm (guix-build): Remove calls to `install-locale',
  `textdomain', etc., now redundant with `initialize-guix'.
* guix/scripts/download.scm (guix-download): Likewise.
* guix/scripts/import.scm (guix-import): Likewise.
* guix/scripts/package.scm (guix-package): Likewise.
* guix/ui.scm: Remove export of `install-locale' and `initialize-guix'.
  (initialize-guix): Add docstring.

Replace individual scripts with master 'guix' script.

* scripts/guix.in: New script.

* Makefile.am (bin_SCRIPTS): Add 'scripts/guix'.  Remove 'guix-build',
  'guix-download', 'guix-import', 'guix-package', and 'guix-gc'.

  (MODULES): Add 'guix/scripts/build.scm', 'guix/scripts/download.scm',
  'guix/scripts/import.scm', 'guix/scripts/package.scm', and
  'guix/scripts/gc.scm'.

* configure.ac (AC_CONFIG_FILES): Add 'scripts/guix'.  Remove 'guix-build',
  'guix-download', 'guix-import', 'guix-package', and 'guix-gc'.

* guix-build.in, guix-download.in, guix-gc.in, guix-import.in,
  guix-package.in: Remove shell script boilerplate.  Move to guix-COMMAND.in
  to guix/scripts/COMMAND.scm.  Rename module from (guix-COMMAND) to
  (guix scripts COMMAND).  Change "guix-COMMAND" to "guix COMMAND" in
  usage help string.

* pre-inst-env.in: Add "@abs_top_builddir@/scripts" to the front of $PATH.
  Export $GUIX_UNINSTALLED.

* tests/guix-build.sh, tests/guix-daemon.sh, tests/guix-download.sh,
  tests/guix-gc.sh, tests/guix-package.sh: Use "guix COMMAND" instead of
  "guix-COMMAND".

* doc/guix.texi: Replace all occurrences of "guix-COMMAND" with
  "guix COMMAND".

* po/POTFILES.in: Update.

Build newest versions unless specified, and implement upgrades.

* gnu/packages.scm (find-newest-available-packages):
  New exported procedure.

* guix-build.in (newest-available-packages, find-best-packages-by-name):
  New procedures.
  (find-package): Use find-best-packages-by-name, to guarantee that
  if a version number is not specified, only the newest versions will
  be considered.

* guix-package.in (%options): Add --upgrade/-u option.
  (newest-available-packages, find-best-packages-by-name, upgradeable?):
  New procedures.
  (find-package): Use find-best-packages-by-name, to guarantee that
  if a version number is not specified, only the newest versions will
  be considered.
  (process-actions): Implement upgrade option.

* doc/guix.texi (Invoking guix-package): In the description of --install,
  mention that if no version number is specified, the newest available
  version will be selected.

Augment `.dir-locals.el'.

* .dir-locals.el: Add more Scheme settings.
* guix-build.in, tests/base32.scm, tests/build-utils.scm,
  tests/builders.scm, tests/derivations.scm, tests/packages.scm,
  tests/snix.scm, tests/store.scm, tests/union.scm, tests/utils.scm:
  Remove redundant Emacs local variable settings.

Gracefully handle failure to install the current locale.

* guix/ui.scm (install-locale): New procedure.
* guix-build.in, guix-download.in, guix-gc.in, guix-import.in,
  guix-package.in: Use it instead of (setlocale LC_ALL "").

guix-build: Fix typo.

* guix-build.in (guix-build)[find-package]: Use `x', not `_', to avoid
  confusion with `gettext'.

guix-build: Allow version-qualified package names.

* guix-build.in (guix-build)[find-package]: New procedure.
  Use it instead of using `find-packages-by-name' directly.
  Suggested by Andreas Enge <andreas@enge.fr>.
* tests/guix-build.sh: Add tests.
* doc/guix.texi (Invoking guix-build): Add `coreutils-8.20' as an
  example.  Fix guile-1.8 example.

distro: Rename (distro) to (gnu packages).

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

Merge branch 'master' into core-updates

Conflicts:
	build-aux/download.scm
	distro/packages/autotools.scm
	distro/packages/base.scm
	distro/packages/bootstrap.scm
	distro/packages/lsh.scm
	distro/packages/make-bootstrap.scm
	distro/packages/ncurses.scm
	distro/packages/perl.scm
	tests/derivations.scm
	tests/union.scm

Update license headers.

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-build: Make `--root' effective for .drv files too.

* guix-build.in (guix-build)[register-root]: Change first argument to
  `paths', which should be a list of store paths.  Update caller to call
  `derivation-path->output-paths' on DRV.  When `derivations-only?',
  also register root for .drv files.

ui: Factorize bug-report information in `--help'.

* 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.

Merge branch 'master' into core-updates

Conflicts:
	distro/packages/multiprecision.scm

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'.