distro: guile-2.0: Propagate libunistring and Libtool.

* distro/base.scm (guile-2.0): Propagate libunistring and Libtool.

distro: guile-1.8: Propagate GMP and Libtool.

* distro/base.scm (guile-1.8): Propagate GMP and Libtool.

Add `package-transitive-inputs'; use it to honor propagated inputs.

* guix/packages.scm (package-transitive-inputs): New procedure.
  (package-derivation): Use it to compute INPUTS.

* tests/packages.scm (dummy-package): New macro.
  ("package-transitive-inputs"): New test.

distro: Add GNU Guile 2.0, released today!

* distro/base.scm (guile-2.0): New variable.

build-system/gnu: Set $PKG_CONFIG_PATH.

* guix/build/gnu-build-system.scm (set-paths): Add `PKG_CONFIG_PATH'.

distro: Add Lout.

* distro/base.scm (lout): New variable.

build-system/gnu: Add `tests?' parameter.

* guix/build-system/gnu.scm (gnu-build): Add `tests?' parameter.
  [builder]: Inherit it.

utils: Have `substitute' restore the file's permission bits.

* guix/build/utils.scm (substitute): Restore FILE's mode before renaming
  TEMPLATE.

utils: Change `substitute' and `substitute*' to work with several regexps.

* guix/build/utils.scm (substitute): Change to accept a `pattern+procs'
  parameter.  Iterate over it.
  (substitute*): Adjust accordingly.

* distro/base.scm (guile-1.8): Adjust accordingly.

distro: gawk: Disable parallel tests.

* distro/base.scm (gawk): Explicitly disable parallel tests.

guix-build: Add `--cores'.

* guix-build.in (leave): New macro, formerly in `guix-build'.
  (show-help): Document `--cores'.
  (%options): Add `--cores'.
  (guix-build): Remove `leave' macro from here.  Pass the `cores' option
  value to `set-build-options'.

build-system/gnu: Support parallel builds and tests.

* guix/build/gnu-build-system.scm (build): Add `parallel-build?'
  parameter; honor it and $NIX_BUILD_CORES.
  (check): Add `parallel-tests?' parameter; likewise.

* guix/build-system/gnu.scm (gnu-build): Add `parallel-build?' and
  `parallel-tests?' parameters.
  [builder]: Inherit them.

utils: Introduce `substitute*', for easier sed-like syntax.

* guix/build/utils.scm (let-matches, substitute*): New macros.

* distro/base.scm (guile-1.8): Use `substitute*' instead of
  `substitute'.  Remove the #:modules argument.

distro: Add GNU Guile 1.8.

* distro/base.scm (guile-1.8): New variable.

* distro/guile-1.8-cpp-4.5.patch: New file.
* Makefile.am (nobase_dist_guilemodule_DATA): Add it.

utils: Make sure `substitute' writes all its output.

* guix/build/utils.scm (substitute): Close OUT before renaming it.

gnu-build-system: Dump the values of environment variables.

* guix/build/gnu-build-system.scm (set-paths): Dump the value of
  environment variables in the `environment-variables' files, similar to
  what Nixpkgs does.

packages: Allow inputs that are local files.

* guix/packages.scm (package-derivation): Add to the store inputs that
  are local files.

build-system/gnu: Add a `patch' phase.

* guix/build/gnu-build-system.scm (patch): New procedure.
  (%standard-phases): Add `patch'.

* guix/build-system/gnu.scm (gnu-build): Add `patches' and `patch-flags'
  parameters.  Pass them on.

build-system/gnu: Make the builder's module list a parameter.

* guix/build-system/gnu.scm (gnu-build): Add a `modules' keyword
  parameter; use it.

Add builder-side utilities for phases, stream editing, & co.

* guix/build/utils.scm (with-directory-excursion): New macro.
  (alist-cons-before, alist-cons-after, alist-replace): New procedures.
  (substitute): New procedure.

* tests/build-utils.scm: New file.

* Makefile.am (TESTS): Add `tests/build-utils.scm'.