Merge branch 'master' into core-updates

doc: rephrase code of conduct.

* doc/contributing.texi (Contributing): Rephrase 'code of conduct'
  section.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

Add "Contributor Covenant".

* CODE-OF-CONDUCT: New file, adapted from
  <http://contributor-covenant.org/version/1/3/0/code_of_conduct.txt>.
* doc/contributing.texi (Contributing): Mention it.
* Makefile.am (EXTRA_DIST): Add 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.

doc: Mention 'guix environment guix'.

* doc/contributing.texi (Building from Git): Mention 'guix environment
guix'.  Remove outdated description of ./bootstrap.  Clarify a few
things.

doc: Remove extraneous "See."

* doc/contributing.texi (Building from Git): Remove extra "See" and use
@xref instead of @pxref.

doc: Fix 'geiser-guile-load-path' example.

Reported by marusich on #guix.

* doc/contributing.texi (The Perfect Setup): Wrap modifying
  'geiser-guile-load-path' into 'with-eval-after-load'.

doc: './pre-inst-env guix pull' won't upgrade local source tree.

* doc/contributing.texi (Running Guix Before It Is Installed): Clarify
  './pre-inst-env guix pull' won't upgrade local source tree.
* doc/guix.texi (Invoking guix pull): Mention ~/.config/guix/latest.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

Merge branch 'master' into dbus-update

doc: Add texinfo to the requirements when building from git.

* doc/contributing.texi (Building from Git): Add GNU Texinfo to the list of
  additional requirements.

doc: Add a REPL example.

* doc/contributing.texi (Running Guix Before It Is Installed): Add REPL
  example.
* doc/emacs.texi (Emacs General info): Add @cindex.

Merge branch 'master' into dbus-update

Add 'guix challenge'.

* guix/scripts/challenge.scm, tests/challenge.scm: New files.
* Makefile.am (MODULES): Add the former.
  (SCM_TESTS): Add the latter.
* doc.am (SUBCOMMANDS): Add 'challenge'.
* doc/guix.texi (Substitutes): Add xref to 'guix challenge'.
  (Invoking guix challenge): New node.
* doc/contributing.texi (Submitting Patches): Add note about using 'guix
  challenge'.
* po/guix/POTFILES.in: Add guix/scripts/challenge.scm.

Merge branch 'master' into core-updates

emacs: Add development utils.

* emacs/guix-guile.el (guix-guile-current-module): New function.
* emacs/guix-devel.el: New file.
* emacs.am (ELFILES): Add it.
* doc/emacs.texi (Emacs Development): New node.
  (Emacs Interface): Add it.
* doc/contributing.texi (The Perfect Setup): Mention it.
* doc/guix.texi (Top): Add it.
* emacs/guix-init.el: Add 'guix-devel-activate-mode-maybe' to
  'scheme-mode-hook'.

Merge branch 'master' into core-updates

doc: Add guidelines for synopses and descriptions.

* doc/guix.texi (Synopses and Descriptions): New node.
* doc/contributing.texi (Submitting Patches): Add item that
  cross-references it.

Merge branch 'master' into core-updates

Add 'guix size'.

* guix/scripts/size.scm: New file.
* Makefile.am (MODULES): Add it.
  (SCM_TESTS): Add tests/size.scm.
* doc.am (SUBCOMMANDS): Add 'size'.
* po/guix/POTFILES.in: Add guix/scripts/size.scm.
* tests/size.scm: New file.
* doc/guix.texi (Packages with Multiple Outputs): Add xref to "Invoking guix
  size".
  (Invoking guix size): New node.
  (Invoking guix gc): Add index for "closure" and xref to the above.
* doc/contributing.texi (Submitting Patches): Use @enumerate for the check
  list.  Add item about 'guix size'.

Merge branch 'master' into core-updates

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