guix build: Add '--check'.

* guix/derivations.scm (build-derivations): Add optional 'mode'
parameter.
* guix/scripts/build.scm (%default-options): Add 'build-mode'.
(show-help, %options): Add '--check'.
(guix-build): Honor 'build-mode' key of OPTS.  Pass it to
'show-what-to-build' and 'build-derivations'.
* doc/guix.texi (Invoking guix build): Document it.
(Substitutes): Mention it.

guix build: Add '--rounds'.

* guix/scripts/build.scm (show-build-options-help)
(%standard-build-options): Add --rounds.
(set-build-options-from-command-line): Honor it.
* doc/guix.texi (Invoking guix build): Document it.
* doc/contributing.texi (Submitting Patches): Mention it.

guix build: Modularize transformation handling.

* guix/scripts/build.scm (options/resolve-packages): Remove.
(options->things-to-build, transform-package-source): New procedure.
(%transformations): New variable.
(options->transformation): New procedure.
(options->derivations): Rewrite to use 'options->things-to-build' and
'options->transformation'.

guix build: Factorize build log query.

* guix/scripts/build.scm (show-build-log): New procedure.
(guix-build): New variable 'items'.  Use it and 'show-build-log'.

Merge branch 'master' into dbus-update

store: Use the daemon's substitute URLs by default.

Partly fixes <http://bugs.gnu.org/20217>.

* guix/store.scm (set-build-options): Change #:substitute-urls to
  default to #f.  Send the 'substitute-urls' pair only if
  SUBSTITUTE-URLS is true.
* guix/scripts/build.scm (set-build-options-from-command-line): Do not
  default to %DEFAULT-SUBSTITUTE-URLS for #:substitute-urls.
* guix/scripts/size.scm (%default-options): Remove 'substitute-urls'.

scripts: build: Add --file option.

* guix/scripts/build.scm (show-help): Add help text for --file option.
  (%options): Add --file option.
  (options/resolve-packages): Handle 'file' options.
* tests/guix-build.sh: Add tests.
* doc/guix.texi ("invoking guix build"): Add doc.

Merge branch 'master' into core-updates

ui: Add 'show-derivation-outputs'.

* guix/scripts/build.scm (guix-build): Extract code from here and move to...
* guix/ui.scm (show-derivation-outputs): ... here.  New procedure.

Add (guix scripts).

* guix/ui.scm: Add missing copyright lines.
  (args-fold*, environment-build-options, %default-argument-handler,
  parse-command-line): Move to ...
* guix/scripts.scm: ...here.  New file.
* guix/scripts/archive.scm: Use it.
* guix/scripts/build.scm: Likewise.
* guix/scripts/download.scm: Likewise.
* guix/scripts/edit.scm: Likewise.
* guix/scripts/environment.scm: Likewise.
* guix/scripts/gc.scm: Likewise.
* guix/scripts/graph.scm: Likewise.
* guix/scripts/hash.scm: Likewise.
* guix/scripts/import/cpan.scm: Likewise.
* guix/scripts/import/cran.scm: Likewise.
* guix/scripts/import/elpa.scm: Likewise.
* guix/scripts/import/gem.scm: Likewise.
* guix/scripts/import/gnu.scm: Likewise.
* guix/scripts/import/hackage.scm: Likewise.
* guix/scripts/import/nix.scm: Likewise.
* guix/scripts/import/pypi.scm: Likewise.
* guix/scripts/lint.scm: Likewise.
* guix/scripts/package.scm: Likewise.
* guix/scripts/publish.scm: Likewise.
* guix/scripts/pull.scm: Likewise.
* guix/scripts/refresh.scm: Likewise.
* guix/scripts/size.scm: Likewise.
* guix/scripts/system.scm: Likewise.
* tests/ui.scm (with-environment-variable, "parse-command-line",
  "parse-command-line and --no options"): Move to ...
* tests/scripts.scm: ...here.  New file.
* Makefile.am (MODULES): Add guix/scripts.scm.
  (SCM_TESTS): Add tests/scripts.scm.
* po/guix/POTFILES.in: Add guix/scripts.scm.

Merge branch 'master' into core-updates

guix build: '--log-file' can return URLs.

* guix/scripts/build.scm (%default-log-urls): New variable.
  (log-url): New procedure.
  (guix-build): Use it.
* doc/guix.texi (Invoking guix build): Document it.

Merge branch 'master' into core-updates

guix build: Add '--substitute-urls' client option.

* guix/scripts/build.scm (%standard-build-options,
  show-build-options-help): Add --substitute-urls=URLS.
  (set-build-options-from-command-line): Honor it.
* guix/store.scm (%default-substitute-urls): Make public.
* doc/guix.texi (Substitutes): Add xref to the client --substitute-urls
  option.
  (Invoking guix build): Document it.
  (Invoking guix-daemon): Add 'daemon-substitute-urls' anchor.

Merge branch 'master' into core-updates

Conflicts:
	gnu/packages/commencement.scm
	gnu/packages/xml.scm

guix build: Allow directories to be passed to --with-source.

* guix/scripts/build.scm (package-with-source)[tarball-base-name]: Gracefully
  handle file names that lack an extension.
  Pass #:recursive? #t to 'download-to-store'.
* guix/download.scm (download-to-store): Add #:recursive? parameter and pass
  it to 'add-to-store'.
* doc/guix.texi (Invoking guix build): Add an example of --with-source with a
  directory.

Merge branch 'master' into core-updates

Merge branch 'master' into gtk-rebuild

Conflicts:
	gnu/packages/gtk.scm

scripts: Move 'set-build-options-from-command-line*' to (guix scripts build) module.

* guix/scripts/build.scm (set-build-options-from-command-line*): New
  procedure.
* guix/scripts/environment.scm (set-build-options-from-command-line*): Delete.

guix: build: Fix indentation for --sources in help output.

* guix/scripts/build.scm (show-help)[--sources]: Make indentation
  consistent with other long options.