syscalls: Add 'swapon' and 'swapoff'.

* guix/build/syscalls.scm (swapon, swapoff): New procedures.
* tests/syscalls.scm ("swapon, ENOENT/EPERM", "swapoff, EINVAL/EPERM"):
  New tests.

syscalls: Add 'all-network-interfaces'.

* guix/build/syscalls.scm (network-interfaces): Update docstring.
  (%interface-line): New variable.
  (all-network-interfaces): New procedure.
* tests/syscalls.scm ("all-network-interfaces"): New test.
  ("network-interfaces"): Change to make sure the result is a subset
  of (all-network-interfaces).

syscalls: Add 'network-interface-flags'.

* guix/build/syscalls.scm (SIOCGIFFLAGS, IFF_UP, IFF_BROADCAST,
  IFF_LOOPBACK, IF_NAMESIZE): New variables.
  (network-interface-flags, loopback-network-interface?): New
  procedures.
* tests/syscalls.scm ("network-interface-flags",
  "loopback-network-interface?"): New tests.

syscalls: Add 'network-interfaces'.

* guix/build/syscalls.scm (SIOCGIFCONF, ifconf-struct,
  ifreq-struct-size): New variables.
  (%ioctl, bytevector->string-list, network-interfaces): New
  procedures.
* tests/syscalls.scm ("network-interfaces"): New test.

gexp: Allow use of high-level objects in #:references-graphs.

* guix/gexp.scm (lower-reference-graphs): New procedure.
  (gexp->derivation)[graphs-file-names]: New procedure.
  Use 'lower-reference-graphs', and augment #:inputs argument as a
  function of #:references-graphs.
* doc/guix.texi (G-Expressions): Adjust 'gexp->derivation' documentation
  accordingly.
* tests/gexp.scm ("gexp->derivation, store copy"): Remove reference to
  TWO in BUILD-DRV.  Use TWO directly in #:references-graphs argument.
  ("gexp->derivation #:references-graphs"): New test.
* gnu/system/vm.scm (qemu-image): Remove variable 'graph'; use INPUTS as
  the #:references-graphs argument to
  'expression->derivation-in-linux-vm'.

vm: Move store copy handling to (guix build store-copy).

* gnu/build/vm.scm (read-reference-graph, populate-store): Move to...
* guix/build/store-copy.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.
* gnu/system/vm.scm (expression->derivation-in-linux-vm): Adjust default
  #:modules values accordingly.
* tests/gexp.scm ("gexp->derivation, store copy"): New test.

profiles: Use a real arrow to denote upgrades in ASCII.

Suggested by Alex Kost.

* guix/profiles.scm (right-arrow): Fall back to "->".
* tests/profiles.scm ("manifest-show-transaction"): Adjust accordingly.

guix lint: Remove "guix lint: " prefix from warnings.

This allows editors to parse warnings correctly.

* guix/scripts/lint.scm (emit-warning): Use 'format' instead of
  'warning', to avoid the "guix lint: " prefix in messages.
* tests/lint.scm (call-with-warnings): Indent.

scripts: add guix lint

* guix/scripts/lint.scm: New file. Defines a 'lint' tool for Guix packages.
* tests/lint.scm: New file.
* Makefile.am (MODULES, SCM_TESTS): Add them.
* po/guix/Makevars: Update appropriately.
* po/guix/POTFILES.in: Update appropriately.
* doc/guix.texi: Document "guix lint".

profiles: Report the old and new version number in upgrades.

* guix/profiles.scm (manifest-lookup): New procedure.
  (manifest-installed?): Use it.
  (manifest-transaction-effects): Return a pair of entries for upgrades.
  (right-arrow): New procedure.
  (manifest-show-transaction)[upgrade-string, →]: New variables.
  Report upgrades using 'upgrade-string'.
* tests/profiles.scm ("manifest-show-transaction"): New test.
  ("manifest-transaction-effects"): Match UPGRADE against a pair.

daemon: Really enable automatic deduplication by default.

* nix/nix-daemon/guix-daemon.cc (main): Set 'autoStoreOptimise' to
  true.  Add 'printMsg' call.
* tests/derivations.scm ("identical files are deduplicated"): New test.

profiles: Compute transaction effects in a functional way.

* guix/profiles.scm (manifest-transaction-effects): New procedure.
  (manifest-show-transaction): Use it instead of locally computing it.
* tests/profiles.scm (glibc): New variable.
  ("manifest-transaction-effects"): New test.

gnu: Split (gnu packages base), adding (gnu packages commencement).

* gnu/packages/base.scm (gnu-make-boot0, diffutils-boot0,
  findutils-boot0, %boot0-inputs, nix-system->gnu-triplet, boot-triplet,
  binutils-boot0, gcc-boot0, perl-boot0, linux-libre-headers-boot0,
  texinfo-boot0, %boot1-inputs, glibc-final-with-bootstrap-bash,
  cross-gcc-wrapper, static-bash-for-glibc, glibc-final,
  gcc-boot0-wrapped, %boot2-inputs, binutils-final, libstdc++,
  gcc-final, ld-wrapper-boot3, %boot3-inputs, bash-final, %boot4-inputs,
  guile-final, gnu-make-final, ld-wrapper, coreutils-final, grep-final,
  %boot5-inputs, %final-inputs, canonical-package, gcc-toolchain,
  gcc-toolchain-4.8, gcc-toolchain-4.9): Move to...
* gnu/packages/commencement.scm: ... here.  New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* build-aux/check-final-inputs-self-contained.scm: Adjust accordingly.
* gnu/packages/cross-base.scm: Likewise.
* gnu/packages/make-bootstrap.scm: Likewise.
* guix/build-system/cmake.scm (cmake-build): Likewise.
* guix/build-system/gnu.scm (standard-packages, gnu-build,
  gnu-cross-build): Likewise.
* guix/build-system/perl.scm (perl-build): Likewise.
* guix/build-system/python.scm (python-build): Likewise.
* guix/build-system/trivial.scm (guile-for-build): Likewise.
* guix/download.scm (url-fetch): Likewise.
* guix/gexp.scm (default-guile): Likewise.
* guix/git-download.scm (git-fetch): Likewise.
* guix/monads.scm (run-with-store): Likewise.
* guix/packages.scm (default-guile): Likewise.
* guix/scripts/package.scm (guix-package): Likewise.
* guix/scripts/refresh.scm: Likewise.
* guix/svn-download.scm (svn-fetch): Likewise.
* tests/builders.scm (%bootstrap-inputs, %bootstrap-search-paths):
  Likewise.
* tests/packages.scm ("GNU Make, bootstrap"): Likewise.
* tests/guix-package.sh: Likewise.
* gnu/services/base.scm: Use 'canonical-package' instead of xxx-final.
* gnu/services/xorg.scm: Likewise.
* gnu/system/vm.scm: Likewise.
* guix/scripts/pull.scm (guix-pull): Likewise.

tests: Fix typo in guix-build.sh.

* tests/guix-build.sh: Refer to the '%bootstrap' variables from (gnu
  packages bootstrap), not (gnu packages base).

guix-register: By default, attempt to deduplicate registered items.

* nix/guix-register/guix-register.cc (GUIX_OPT_DEDUPLICATE): New macro.
  (options): Add --no-deduplication.
  (deduplication): New variable.
  (parse_opt): Handle GUIX_OPT_DEDUPLICATE.
  (register_validity): Add 'optimize' parameter and honor it.
  (main): Move 'store' instanatiation after 'settings.nixStore'
  assignment.
* tests/guix-register.sh: Add test for deduplication.
* guix/nar.scm (finalize-store-file): Update comment above
  'register-path' call.

Factorize test suite support in (guix tests).

* guix/tests.scm: New file.
* Makefile.am (noinst_DATA): New variable.
  (GOBJECTS): Add guix/tests.go.
* tests/builders.scm (%store): Use 'open-connection-for-tests'
  from (guix tests).
* tests/derivations.scm: Likewise.
* tests/monads.scm: Likewise.
* tests/packages.scm: Likewise.
* tests/profiles.scm: Likewise.
* tests/union.scm: Likewise.
* tests/gexp.scm: Likewise.
  (guile-for-build): Remove.  Use (%guile-for-build) instead.
* tests/nar.scm (make-random-bytevector, %seed, random-text): Remove.
  (populate-file): Change 'make-random-bytevector' to 'random-bytevector'.
  Use (guix tests).
* tests/store.scm (%seed, random-text): Remove.
  Use (guix tests).

profiles: Produce a top-level Info 'dir' file.

Fixes <http://bugs.gnu.org/18305>.
Reported by Brandon Invergo <brandon@gnu.org>.

* guix/profiles.scm (manifest-inputs, info-dir-file): New procedures.
  (profile-derivation): Use them.  Add #:info-dir? parameter and honor
  it.
* guix/scripts/package.scm (guix-package): Call 'profile-derivation'
  with #:info-dir? #f when the 'bootstrap? option is set.
* tests/profiles.scm ("profile-derivation"): Pass #:info-dir? #f.

profiles: Add 'manifest-transaction'.

* guix/profiles.scm (<manifest-transaction>): New record-type.
  (manifest-perform-transaction): New procedure.
  (manifest-show-transaction): New procedure.
* tests/profiles.scm ("manifest-perform-transaction"): New test.

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

gexp: Add 'ungexp-native' and 'ungexp-native-splicing'.

* guix/gexp.scm (<gexp>)[natives]: New field.
  (write-gexp): Use both 'gexp-references' and
  'gexp-native-references'.
  (gexp->derivation): Use both 'gexp-inputs' and 'gexp-native-inputs',
  and append them.
  (gexp-inputs): Add 'references' parameter and honor it.
  (gexp-native-inputs): New procedure.
  (gexp->sexp)[reference->sexp]: Add 'native?' parameter and honor it.
  Use it, and use 'gexp-native-references'.
  (gexp)[collect-native-escapes]: New procedure.
  [escape->ref]: Handle 'ungexp-native' and 'ungexp-native-splicing'.
  [substitute-ungexp, substitute-ungexp-splicing]: New procedures.
  [substitute-references]: Use them, and handle 'ungexp-native' and
  'ungexp-native-splicing'.
  Adjust generated 'make-gexp' call to provide both normal references
  and native references.
  [read-ungexp]: Support 'ungexp-native' and
  'ungexp-native-splicing'.
  Add reader extension for #+.
* tests/gexp.scm (gexp-native-inputs): New procedure.
  (gexp->sexp*): Add 'target' parameter.
  ("ungexp + ungexp-native",
  "input list + ungexp-native",
  "input list splicing + ungexp-native-splicing",
  "gexp->derivation, ungexp-native",
  "gexp->derivation, ungexp + ungexp-native"): New tests.
  ("sugar"): Add tests for #+ and #+@.
* doc/guix.texi (G-Expressions): Document 'ungexp-native' et al.

gexp: Add #:target parameter to 'gexp->derivation'.

* guix/gexp.scm (lower-inputs): Add #:system and #:target.  Use
  'package->cross-derivation' when TARGET is true.  Honor SYSTEM.
  (gexp->derivation): Add #:target argument.  Pass SYSTEM and TARGET to
  'lower-inputs' and 'gexp->sexp'.
  (gexp->sexp): Add #:system and #:target.  Pass them in recursive call
  and to 'package-file'.
* tests/gexp.scm (gexp->sexp*): Add 'system' and 'target' parameters.
  ("gexp->derivation, cross-compilation"): New test.