build: Skip one 'package-source-derivation' test when networking is missing.

* tests/packages.scm ("package-source-derivation, snippet"): Skip when
  networking is missing.

Merge branch 'core-updates'

Conflicts:
	gnu/packages/gnunet.scm

Merge branch 'master' into core-updates

Conflicts:
	guix/packages.scm

packages: 'package-field-location' returns a relative file name.

* guix/packages.scm (package-field-location): Set
  %FILE-PORT-NAME-CANONICALIZATION.
* tests/packages.scm ("package-field-location, relative file name"): New
  test.

tests: Adjust to bootstrap tarball updates.

Reported by Mark H. Weaver <mhw@netris.org>.

* tests/packages.scm ("package-source-derivation, snippet"): Change to
  "guile-2.0.9.tar.xz".
* tests/union.scm ("union-build"): Check or include/c++ being a symlink.

packages: Suitably cope with indirect store paths as package sources.

* guix/packages.scm (package-source-derivation): Don't let indirect
  store paths pass through.
* tests/packages.scm ("package-source-derivation, indirect store path"):
  New test.

Merge branch 'master' into core-updates

Conflicts:
	guix/packages.scm

packages: Add a 'snippet' field to <origin>.

* guix/packages.scm (<origin>): Add 'snippet', 'modules', and
  'imported-modules' fields.
  (patch-and-repack): Make 'inputs' a keyword parameter.  Add 'snippet',
  'modules', and 'imported-modules' parameters.  Accept SOURCE as a raw
  file name.  Insert SNIPPET in BUILDER.  Pass IMPORTED-MODULES to
  'build-expression->derivation'.
  (package-source-derivation): Pass the extra arguments to
  'patch-and-repack'.
* tests/packages.scm ("package-source-derivation, snippet"): New test.
* doc/guix.texi (Defining Packages): Mention the 'patches' and 'snippet'
  fields.
  (Invoking guix build): Tell that --source has patches and snippets
  applied.
  (Software Freedom): Mention packages that contain non-free code.

build-system/trivial: Take the 'source' field into account.

* guix/build-system/trivial.scm (trivial-build): When SOURCE is true,
  add it to INPUTS.
  (trivial-cross-build): Likewise.
* tests/packages.scm ("trivial with source"): New test.

Merge branch 'master' into core-updates

derivations: 'derivation' and related procedures return a single value.

* guix/derivations.scm (derivation->output-path,
  derivation->output-paths): New procedures.
  (derivation-path->output-path): Use 'derivation->output-path'.
  (derivation-path->output-paths): Use 'derivation->output-paths'.
  (derivation): Accept 'derivation?' objects as inputs.  Return a single
  value.
  (build-derivations): New procedure.
  (compiled-modules): Use 'derivation->output-paths'.
  (build-expression->derivation)[source-path]: Add case for when the
  input matches 'derivation?'.
  [prologue]: Accept 'derivation?' objects in INPUTS.
  [mod-dir, go-dir]: Use 'derivation->output-path'.
* guix/download.scm (url-fetch): Adjust to the single-value return.
* guix/packages.scm (package-output): Use 'derivation->output-path'.
* guix/scripts/build.scm (guix-build): When the argument is
  'derivation-path?', pass it through 'read-derivation'.
  Use 'derivation-file-name' to print out the .drv file names, and to
  register them.  Use 'derivation->output-path' instead of
  'derivation-path->output-path'.
* guix/scripts/package.scm (roll-back): Adjust to the single-value
  return.
  (guix-package): Use 'derivation->output-path'.
* guix/ui.scm (show-what-to-build): Adjust to deal with 'derivation?'
  objects instead of .drv file names.
* gnu/system/grub.scm (grub-configuration-file): Use
  'derivation->output-path' instead of 'derivation-path->output-path'.
* gnu/system/vm.scm (qemu-image, system-qemu-image): Likewise.
* tests/builders.scm, tests/derivations.scm, tests/packages.scm,
  tests/store.scm, tests/union.scm: Adjust to the new calling
  convention.
* doc/guix.texi (Defining Packages, The Store, Derivations): Adjust
  accordingly.

packages: Allow file names as package sources.

* guix/packages.scm (package-source-derivation): Add cases for SOURCE as
  a store path or user file.
* tests/packages.scm ("package-source-derivation, file",
  "package-source-derivation, store path"): New tests.

tests: Adjust `package-field-location' test for Guile <= 2.0.6.

* tests/packages.scm ("package-field-location"): Check the result of
  `read-at' against both VALUE and (FIELD VALUE).
  Reported by Matthew Lien - 練喆明" <bluet@bluet.org>.

packages: Raise an error condition a cross builder is needed but unavailable.

* guix/packages.scm (&package-cross-build-system-error): New condition type.
  (package-cross-derivation): Raise &package-cross-build-system-error
  when the build system doesn't support cross builds.
* guix/ui.scm (call-with-error-handling): Add
  package-cross-build-system-error? case.
* tests/packages.scm ("package-cross-derivation, no cross builder"): New test.

build-system/trivial: Implement the cross-build protocol.

* guix/build-system/trivial.scm (guile-for-build): New procedure.
  (trivial-build): Use it.
  (trivial-cross-build): New procedure.
  (trivial-build-system): Use it.

packages: Implement `package-cross-derivation'.

* guix/packages.scm (package-transitive-target-inputs,
  package-transitive-native-inputs): New procedures.
  (package-derivation): Parametrize `%current-target-system'.
  (package-cross-derivation): Implement.
* guix/utils.scm (%current-target-system): New variable.
* tests/packages.scm ("package-cross-derivation"): New test.
* doc/guix.texi (Defining Packages): Document
  `package-cross-derivation'.

Merge branch 'core-updates'

Merge branch 'master' into core-updates

Conflicts:
	Makefile.am
	gnu/packages/autotools.scm
	gnu/packages/guile.scm
	gnu/packages/python.scm
	gnu/packages/shishi.scm
	guix/gnu-maintenance.scm
	guix/scripts/build.scm
	guix/scripts/gc.scm
	guix/scripts/package.scm
	guix/scripts/substitute-binary.scm
	guix/ui.scm
	nix/nix-daemon/guix-daemon.cc
	test-env.in
	tests/nar.scm
	tests/store.scm

packages: Use `read' and source properties for `package-field-location'.

* guix/packages.scm (package-field-location): Rewrite using `read' and
  source properties.  Change to return #f upon failure.
* tests/packages.scm ("package-field-location"): Check for #f upon failure.
* build-aux/sync-synopses.scm: Adjust accordingly.

packages: Add `package-field-location'.

* guix/packages.scm (package-field-location): New procedure.
* build-aux/sync-synopses.scm: Use it instead of `package-location'.
* tests/packages.scm ("package-field-location"): New test.