ui: Factorize command-line + env. var. option parsing.

* guix/ui.scm (%default-argument-handler, parse-command-line): New
  procedures.
  (environment-build-options): Make private.
* guix/scripts/archive.scm (guix-archive)[parse-options,
  parse-options-from]: Remove.  Use 'parse-command-line' instead.
* guix/scripts/build.scm (guix-build): Likewise.
* guix/scripts/environment.scm (guix-environment): Likewise.
* guix/scripts/package.scm (guix-package): Likewise.
* guix/scripts/system.scm (guix-system): Likewise.
* tests/ui.scm (with-environment-variable): New macro.
  ("parse-command-line"): New test.

monads: Move '%store-monad' and related procedures where they belong.

This turns (guix monads) into a generic module for monads, and moves the
store monad and related monadic procedures in their corresponding
module.

* guix/monads.scm (store-return, store-bind, %store-monad, store-lift,
  text-file, interned-file, package-file, package->derivation,
  package->cross-derivation, origin->derivation, imported-modules,
  compiled, modules, built-derivations, run-with-store): Move to...
* guix/store.scm (store-return, store-bind, %store-monad, store-lift,
  text-file, interned-file): ... here.
  (%guile-for-build): New variable.
  (run-with-store): Moved from monads.scm.  Remove default value for
  #:guile-for-build.
* guix/packages.scm (default-guile): Export.
  (set-guile-for-build): New procedure.
  (package-file, package->derivation, package->cross-derivation,
  origin->derivation): Moved from monads.scm.
* guix/derivations.scm (%guile-for-build): Remove.
  (imported-modules): Rename to...
  (%imported-modules): ... this.
  (compiled-modules): Rename to...
  (%compiled-modules): ... this.
  (built-derivations, imported-modules, compiled-modules): New
  procedures.
* gnu/services/avahi.scm, gnu/services/base.scm, gnu/services/dbus.scm,
  gnu/services/dmd.scm, gnu/services/networking.scm,
  gnu/services/ssh.scm, gnu/services/xorg.scm, gnu/system/install.scm,
  gnu/system/linux-initrd.scm, gnu/system/shadow.scm, guix/download.scm,
  guix/gexp.scm, guix/git-download.scm, guix/profiles.scm,
  guix/svn-download.scm, tests/monads.scm: Adjust imports accordingly.
* guix/monad-repl.scm (default-guile-derivation): New procedure.
  (store-monad-language, run-in-store): Use it.
* build-aux/hydra/gnu-system.scm (qemu-jobs): Add explicit
  'set-guile-for-build' call.
* guix/scripts/archive.scm (derivation-from-expression): Likewise.
* guix/scripts/build.scm (options/resolve-packages): Likewise.
* guix/scripts/environment.scm (guix-environment): Likewise.
* guix/scripts/system.scm (guix-system): Likewise.
* doc/guix.texi (The Store Monad): Adjust module names accordingly.

Merge branch 'master' into 'core-updates'.

guix: scripts: Parse $GUIX_BUILD_OPTIONS separately.

Appending to "raw" args broke optional parameters in 'guix package -I'
and 'guix package -A', and possibly other places.  Therefore, switch to
parsing each set of options on its own and append resulting alists
together afterwards.

* guix/scripts/archive.scm (parse-options-from): Rename from
  (parse-options) and add explicit argument.  New form of (parse-options)
  using its old algorithm via -from function.
* guix/scripts/build.scm: Ditto.
* guix/scripts/environment.scm: Ditto.
* guix/scripts/package.scm: Ditto.
* guix/scripts/system.scm: Ditto.
* tests/guix-package.sh: Add test.
* doc/guix.texi (Invoking guix build): Make it clear that the options
  are parsed independently.

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

guix: scripts: Add GUIX_BUILD_OPTIONS environment handling.

* doc/guix.texi (Invoking guix build): Mention 'GUIX_BUILD_OPTIONS'.
* guix/scripts/archive.scm: (append args (environment-build-options)).
* guix/scripts/build.scm: Ditto.
* guix/scripts/environment.scm: Ditto.
* guix/scripts/package.scm: Ditto.
* guix/scripts/system.scm: Ditto.
* guix/ui.scm (environment-build-options): New function.
* guix/utils.scm (arguments-from-environment-variable): New function.
* tests/guix-build.sh: Add tests.
* test-env.in: Unset GUIX_BUILD_OPTIONS.

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

guix build: Add '--max-jobs' option.

Suggested by Deck Pickard <deck.r.pickard@gmail.com>.

* guix/scripts/build.scm (show-build-options-help): Document
  --max-jobs.
  (set-build-options-from-command-line): Pass #:max-build-jobs.
  (%standard-build-options): Add --max-jobs.
* doc/guix.texi (Invoking guix-daemon): Document the meaning of
  '--max-jobs 0'.
  (Invoking guix build): Document --max-jobs, with a reference to
  "Invoking guix-daemon'.

packages: Implement grafts.

Thanks to Mark H. Weaver <mhw@netris.org> for insightful discussions
and suggestions.

* guix/packages.scm (<package>)[graft]: New field.
  (patch-and-repack): Invoke 'package-derivation' with #:graft? #f.
  (package-source-derivation): Likewise.  Do not use (%guile-for-build)
  in call to 'patch-and-repack', and we could end up using a grafted
  Guile.
  (expand-input): Likewise, also for 'package-cross-derivation' call.
  (package->bag): Add #:graft? parameter.  Honor it.  Use 'strip-append'
  instead of 'package-full-name'.
  (input-graft, input-cross-graft, bag-grafts, package-grafts): New
  procedures.
  (package-derivation, package-cross-derivation): Add #:graft? parameter
  and honor it.
* gnu/packages/bootstrap.scm (package-with-bootstrap-guile): Add
  recursive call on 'graft'.
* guix/build-system/gnu.scm (package-with-explicit-inputs,
  package-with-extra-configure-variable, static-package): Likewise.
  (gnu-build): Use the ungrafted Guile to avoid full rebuilds.
  (gnu-cross-build): Likewise.
* guix/build-system/cmake.scm (cmake-build): Likewise.
* guix/build-system/glib-or-gtk.scm (glib-or-gtk-build): Likewise.
* guix/build-system/perl.scm (perl-build): Likewise.
* guix/build-system/python.scm (python-build): Likewise.
* guix/build-system/ruby.scm (ruby-build): Likewise.
* guix/build-system/trivial.scm (guile-for-build): Likewise.
* tests/packages.scm ("package-derivation, direct graft",
  "package-cross-derivation, direct graft", "package-grafts,
  indirect grafts", "package-grafts, indirect grafts, cross",
  "package-grafts, indirect grafts, propagated inputs",
  "package-derivation, indirect grafts"): New tests.
  ("bag->derivation", "bag->derivation, cross-compilation"): Wrap in
  'parameterize'.
* doc/guix.texi (Security Updates): New node.
  (Invoking guix build): Document --no-graft.

guix build: Add -L/--load-path as a common option.

* guix/scripts/build.scm (show-build-options-help): Document -L.
  (%standard-build-options): Add -L/--load-path.
* tests/guix-package.sh: Test it.

Merge branch 'master' into core-updates

Move specification->package to gnu/packages.scm.

* guix/scripts/build.scm (specification->package): Move from here...
* gnu/packages.scm: ... to here.

Merge branch 'master' into core-updates

guix build: Allow gexps to be passed to '-e'.

* guix/ui.scm (%guix-user-module): New variable.
  (read/eval): Pass it as the second argument to 'eval'.
* guix/scripts/build.scm (options/resolve-packages): Add case for
  'gexp?'.
* tests/guix-build.sh: Add tests.
* doc/guix.texi (Invoking guix build): Document '-e gexp'.
guxi build: Allow gexps to be passed to '-e'.

* guix/ui.scm (%guix-user-module): New variable.
  (read/eval): Pass it as the second argument to 'eval'.
* guix/scripts/build.scm (options/resolve-packages): Add case for
  'gexp?'.
* tests/guix-build.sh: Add tests.
* doc/guix.texi (Invoking guix build): Document '-e gexp'.

guix build: Only 'guix build' sets #:print-build-trace.

This makes 'guix package' et al. slightly less verbose, by not emitting
"@ substituter-started" lines and similar.

* guix/scripts/build.scm (set-build-options-from-command-line): Pass
  #:print-build-trace.
  (%default-options): Add 'print-build-trace?'.

Merge branch 'master' into core-updates

guix build: Support '--with-source' along with '-e'.

* guix/scripts/build.scm (derivation-from-expression): Remove.
  (options->derivations): Handle pairs of the form
  "('argument . (? derivation?))".
  (options/resolve-packages): Add 'store' parameter; update caller.  Add
  'system' variable.  Add case for 'expression pairs.
* guix/scripts/archive.scm (derivation-from-expression): New procedure.

guix build: Add '--with-source'.

* guix/scripts/build.scm (package-with-source): New procedure.
  (show-help): Add '--with-source'.
  (%options): Likewise.
  (options->derivations): Call 'options/with-source' and
  'options/resolve-packages'.
  (options/resolve-packages, options/with-source): New procedures.
* doc/guix.texi (Invoking guix build): Document '--with-source'.

Merge branch 'master' into core-updates

guix build: Add '--timeout' to the common build options.

* guix/scripts/build.scm (show-build-options-help): Document
  '--timeout'.
  (set-build-options-from-command-line): Pass #:timeout to
  'set-build-options'.
  (%standard-build-options): Add '--timeout'.
* doc/guix.texi (Invoking guix build): Document it.

guix package: Use the common build options from (guix scripts build).

* guix/scripts/build.scm (%standard-build-options): Change option
  handlers to support multiple seeds.
* guix/scripts/package.scm (show-help): Remove --dry-run, --fallback,
  --no-substitutes, and --max-silent-time.
  (%options): Likewise, and add %STANDARD-BUILD-OPTIONS.
  (%default-options): Add 'verbosity'.
  (guix-package): Call 'set-build-options-from-command-line' instead of
  'set-build-options'.

Merge branch 'master' into core-updates

Conflicts:
	gnu-system.am