packages: Have `package-derivation' return a <derivation> as a second value.

* guix/packages.scm (cache): Change the `drv' argument to `thunk'.
  Memoize all the return values of THUNK.
  (cached-derivation): Remove.
  (cached): New macro.
  (package-derivation): Use `cached' instead of `(or (cached-derivation) …)'.
* doc/guix.texi (Defining Packages): Update accordingly.

distro: Rename (distro) to (gnu packages).

* distro.scm: Rename to...
* gnu/packages.scm: ... this.  Update all users accordingly.
* Makefile.am (MODULES): Adjust accordingly.
* po/POTFILES.in: Likewise.

distro: Change the module name space to (gnu ...).

* distro: Rename to...
* gnu: ... this.  Update module names accordingly.
* Makefile.am: Adjust accordingly.
* po/POTFILES.in: Likewise.
* distro.scm: Search for files under /gnu/packages instead of
  /distro/packages.
* gnu/packages/base.scm (ld-wrapper-boot3): Likewise.

Merge branch 'master' into core-updates

Conflicts:
	build-aux/download.scm
	distro/packages/autotools.scm
	distro/packages/base.scm
	distro/packages/bootstrap.scm
	distro/packages/lsh.scm
	distro/packages/make-bootstrap.scm
	distro/packages/ncurses.scm
	distro/packages/perl.scm
	tests/derivations.scm
	tests/union.scm

Update license headers.

Change all license headers, except guix/build/* and ld-wrapper.scm, with
this code:

  (use-modules (guix build utils)
	       (srfi srfi-1))

  (fluid-set! %default-port-encoding "UTF-8")

  (substitute* (remove (lambda (f)
			 (or (string-contains f ".tar.")
			     (string-contains f ".git/")
			     (string-contains f ".so")
			     (string-suffix? ".o" f)
			     (string-suffix? ".a" f)
			     (string-suffix? ".go" f)
			     (string-suffix? ".pdf" f)
			     (string-suffix? ".png" f)
			     (string-suffix? ".info" f)
			     (equal? (basename f) "guix-daemon")
			     (equal? (basename f) "nix-setuid-helper")
			     (string-contains f "nix-upstream/")
			     (string-contains f "distro/packages/bootstrap/")))
		       (find-files "." "\\.[a-z]+$"))
    (("^([[:graph:]]+) This file is part of Guix." _ comment-start)
     (string-append comment-start " This file is part of GNU Guix."))
    (("^([[:graph:]]+) Guix --- Nix package management.*" _ comment-start)
     (string-append comment-start
		    " GNU Guix --- Functional package management for GNU\n"))
    (("^([[:graph:]]+) Guix is " _ comment-start)
     (string-append comment-start " GNU Guix is "))
    (("^([[:graph:]]+) along with Guix." _ comment-start)
     (string-append comment-start " along with GNU Guix."))
    (("^([[:graph:]]+) Copyright \\(C\\)" _ comment-start)
     (string-append comment-start " Copyright ©")))

Change headers using C-style comments manually.

Merge branch 'nix-integration'

Conflicts:
	tests/guix-package.sh

tests: Skip network-dependent tests when the network is unreachable.

* tests/builders.scm (network-reachable?): New variable.
  ("url-fetch", "gnu-build"): Skip unless NETWORK-REACHABLE?.
* tests/derivations.scm (%coreutils): Check for network access.
  ("build-expression->derivation with one input"): Skip when %COREUTILS
  is #f.
* tests/guix-package.sh: Skip installation of GNU Make when the network
  is unreachable.
* tests/packages.scm ("GNU Make, bootstrap"): Likewise.
* tests/union.scm ("union-build"): Likewise.

Merge branch 'master' into nix-integration

derivations: Fix erroneous call to `add-to-store' for local files as input.

* guix/derivations.scm (derivation)[inputs]: Fix typo in call to
  `add-to-store'.
* tests/derivations.scm ("derivation with local file as input"): New test.
* tests/packages.scm ("trivial with local file as input"): New test.

distro: Add `fold-packages'.

* distro.scm (fold-packages): New procedure.
  (find-packages-by-name): Use it instead of hand-written traversal;
  remove `package?' checks from `right-package?'.
* tests/packages.scm ("fold-packages"): New test.

tests: Choose a less expensive test for packages.

* tests/packages.scm (%bootstrap-inputs): Remove.
  ("GNU Hello"): Rename to...
  ("GNU Make, bootstrap"): ... this.  Build GNU-MAKE-BOOT0 instead of
  HELLO.

distro: Move bootstrap packages to (distro packages bootstrap).

* distro/packages/base.scm (glibc-dynamic-linker, %bootstrap-guile,
  bootstrap-origin, package-from-tarball, %bootstrap-base-url,
  %bootstrap-coreutils&co, %bootstrap-binutils, %bootstrap-glibc,
  %bootstrap-gcc, %bootstrap-inputs, package-with-bootstrap-guile): Move
  to ...
* distro/packages/bootstrap.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.
* tests/builders.scm: Use (distro packages bootstrap).
  (%bootstrap-guile): Remove.
* tests/packages.scm: Likewise.
* tests/union.scm: Likewise, and remove @@ to access %bootstrap-inputs.
* tests/derivations.scm: Use (distro packages bootstrap) and remove @@
  to access %bootstrap-coreutils&co.
* HACKING (When the platform is supported by Nixpkgs): Update
  accordingly.

packages: `description' → `synopsis', `long-description' → `description'.

* guix/packages.scm (<package>): Rename `description' to `synopsis', and
  `long-description' to `description'.
* tests/packages.scm, distro/packages/base.scm,
  distro/packages/databases.scm, distro/packages/guile.scm,
  distro/packages/typesetting.scm:  Update accordingly.
* po/Makevars (XGETTEXT_OPTIONS): Update `--keyword' flags accordingly.

tests: Run without substitutes.

* tests/builders.scm, tests/derivations.scm, tests/packages.scm: Set
  #:use-substitutes? #f for %STORE.

tests: Use our own bootstrap tools.

* tests/builders.scm (%bootstrap-inputs): Use %BOOT0-INPUTS from the distro.
* tests/packages.scm (%bootstrap-inputs): Likewise.
* tests/derivations.scm (%coreutils): Alias for %BOOTSTRAP-COREUTILS&CO.

packages: Add support for system-dependent inputs.

* guix/packages.scm (package-derivation)[intern]: New procedure.  Pass
  #t as the `recursive?' argument, instead of #f.
  [expand-input]: New procedure, with code formerly in the body.
  Support inputs where the input is a procedure returning a file name or
  an <origin>.
  Use `expand-input' in the body.

* tests/packages.scm ("trivial with system-dependent input"): New test.

tests: Use bootstrap and Nixpkgs inputs to be less costly.

* tests/builders.scm (%bootstrap-inputs, %bootstrap-guile): New
  variables.
  ("gnu-build"): Use them, by setting `#:implicit-inputs? #f' and `#:guile'.

* tests/packages.scm (%bootstrap-inputs, %bootstrap-guile): New
  variables.
  ("trivial"): Pass `#:guile %bootstrap-guile'.
  ("GNU Hello"): Use `package-with-explicit-inputs' to use
  %BOOTSTRAP-GUILE and %BOOTSTRAP-INPUTS.

distro: Rename (distro ...) to (distro packages ...).

* distro/base.scm, distro/ld-wrapper.scm: Move to `distro/packages'.
  Adjust LD-WRAPPER-BOOT3 input file name accordingly.
* Makefile.am (MODULES): Adjust accordingly.
* distro.scm (%distro-module-directory): Change to "/distro/packages".
* guix/build-system/gnu.scm (standard-inputs): Change module name
  to (distro packages base).
* tests/packages.scm (test-packages): Likewise.

Add (guix build-system trivial).

* guix/build-system/trivial.scm: New file.
* Makefile.am (MODULES): Add it.
* tests/packages.scm ("trivial"): New test.

* guix/packages.scm (package-derivation): Allow SOURCE to be #f.

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.