Introduce the 'GUIX_PACKAGE_PATH' environment variable.

* gnu/packages.scm (%package-module-path): Honor $GUIX_PACKAGE_PATH.
* test-env.in: Unset 'GUIX_PACKAGE_PATH'.
* tests/guix-package.sh: Test it.
* doc/guix.texi (Package Modules): Document it.

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 'core-updates'

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.

utils: Allow wrap-program to be called multiple times.

* guix/build/utils.scm (wrap-program): Multiple invocations of
  wrap-program for the same file create successive wrappers.  Adjust
  docstring.
* tests/build-utils.scm: Test new wrap-program behavior.
  (%store): New variable.

Merge branch 'master' into core-updates

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.

Merge branch 'master' into core-updates

Conflicts:
	gnu/packages/base.scm

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).