download: Add kernel.org mirrors.

* guix/download.scm (%mirrors): Add `kernel.org' mirrors.

download: Keep only one slash when concatenating URIs.

* guix/build/download.scm (url-fetch)[uri-vicinity]: New procedure.
  [maybe-expand-mirrors]: Use it.

packages: Add missing export.

* guix/packages.scm: Export `package-home-page'.

guix-package: Add `--list-available'.

* guix-package.in (show-help, %options): Add `--list-available'.
  (guix-package)[process-query]: Add support for `--list-available'.
* doc/guix.texi (Invoking guix-package): Document it.
* tests/guix-package.sh: Add test.

* guix/ui.scm (location->string): New procedure.
* guix/utils.scm: Export <location>.

guix-download: Use code from (guix build download).

* guix-download.in (http-fetch, ftp-fetch): Remove.
  (fetch-and-store): Replace `uri' parameter with `name', for the output
  file name.  Redirect the output of `fetch' to the error port.
  (guix-download): Call `url-fetch' for all URI schemes except `file'.
  Handle PATH equal to #f.
* guix/download.scm: Export `%mirrors'.
* tests/guix-download.sh: Change erroneous URL, because URLs at
  example.com are all valid redirections.

download: Add support for mirror:// URLs.

* guix/download.scm (%mirrors): New variable.  Mirror lists taken from
  Nixpkgs.
  (url-fetch): New `mirrors' keyword parameter.
  [builder]: Pass it.

* guix/build/download.scm (url-fetch): New `mirrors' keyword parameter.
  [maybe-expand-mirrors]: New procedure.
  [uri]: Use it.

download: Follow HTTP redirections.

* guix/build/download.scm (http-fetch): Follow the redirection when CODE
  is 302.

Remove (guix http) and (guix ftp).

* guix/ftp.scm, guix/http.scm, guix/build/ftp.scm, guix/build/http.scm:
  Remove.
* Makefile.am (MODULES): Likewise.
* tests/builders.scm, distro/packages/base.scm,
  distro/packages/bash.scm, distro/packages/bdw-gc.scm,
  distro/packages/compression.scm, distro/packages/gawk.scm,
  distro/packages/gnupg.scm, distro/packages/gperf.scm,
  distro/packages/guile.scm, distro/packages/libffi.scm,
  distro/packages/libsigsegv.scm, distro/packages/libtool.scm,
  distro/packages/libunistring.scm, distro/packages/lout.scm,
  distro/packages/m4.scm, distro/packages/multiprecision.scm,
  distro/packages/ncurses.scm, distro/packages/perl.scm,
  distro/packages/pkg-config.scm, distro/packages/pth.scm,
  distro/packages/readline.scm, distro/packages/recutils.scm: Use
  `url-fetch' instead of `http-fetch' and `ftp-fetch'.
* distro/packages/bootstrap.scm: Likewise
  (bootstrap-origin): Remove references to `http-fetch' and
  `ftp-fetch'.
* guix.scm (%public-modules): Remove `http' and `ftp'; add `download'.

Add (guix download) and (guix build download).

* guix/download.scm, guix/build/download.scm: New files.
* Makefile.am (MODULES): Add them.
* tests/builders.scm ("url-fetch"): New test.
* distro/packages/bootstrap.scm (bootstrap-origin): Support
  `url-fetch'.
* guix/snix.scm (snix-derivation->guix-package): Use `url-fetch' instead
  of `http-fetch'.

Move base32 code to (guix base32).

* guix/utils.scm (bytevector-quintet-ref, bytevector-quintet-ref-right,
  bytevector-quintet-length, bytevector-quintet-fold,
  bytevector-quintet-fold-right, make-bytevector->base32-string,
  %nix-base32-chars, %rfc4648-base32-chars, bytevector->base32-string,
  bytevector->nix-base32-string, bytevector-quintet-set!,
  bytevector-quintet-set-right!, base32-string-unfold,
  base32-string-unfold-right, make-base32-string->bytevector,
  base32-string->bytevector, nix-base32-string->bytevector): Move to...
* guix/base32.scm: ... here.  New file.

* tests/utils.scm (%nix-hash, "bytevector->base32-string",
  "base32-string->bytevector", "nix-base32-string->bytevector", "sha256
  & bytevector->base32-string"): Move to...
* tests/base32.scm: ... here.  New file

* guix-download.in, guix/derivations.scm, guix/packages.scm,
  guix/snix.scm, tests/builders.scm, tests/derivations.scm: Adjust
  accordingly.
* guix.scm (%public-modules): Add `base32'.

http: Add informative output.

* guix/build/http.scm (http-fetch): Emit message indicating the
  download.

http: Check the HTTP response code, and bail if not 200.

* guix/build/http.scm (http-fetch): Check RESP's code; error out when
  it's not 200.

derivations: build-expression->derivation: Builder only refers to sources.

* guix/derivations.scm (build-expression->derivation)[source-path]: New
  procedure.
  [builder]: Pass only sources as references.  This fixes a bug whereby
  changing a fixed-output drv referred to by a builder would cause the
  builder's hash to change, thereby leading to a full rebuild.
* tests/derivations.scm ("build-expression->derivation with a
  fixed-output input"): New test.

store: Document `add-to-store' hack for `fixed?'.

* guix/store.scm (add-to-store): Document that `fixed?' must be #t.

build-system/gnu: Add `static-libgcc-package' & supporting procedure.

* guix/build-system/gnu.scm (package-with-extra-configure-variable,
  static-libgcc-package): New procedures.

utils: Add `default-keyword-arguments' and `substitute-keyword-arguments'.

* distro/packages/base.scm (default-keyword-arguments,
  substitute-keyword-arguments): Move to...
* guix/utils.scm: ... here.

Add (guix snix) and the `guix-import' command.

* guix/snix.scm, tests/snix.scm, guix-import.in: New files.
* configure.ac: Output `guix-import' and make it executable.
* Makefile.am (bin_SCRIPTS): Add `guix-import'.
  (MODULES): Add `guix/snix.scm'.
  (TESTS): Add `tests/snix.scm'.

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.

utils: Add `package-name->name+version'.

* guix/utils.scm (package-name->name+version): New procedure.
* guix-package.in (guix-package)[find-package]: Use it.
* tests/utils.scm ("package-name->name+version"): New test.

build: Require GNU libgcrypt.

* guix/utils.scm (sha256): Remove Coreutils- and libchop-based
  implementations.
* README: Update accordingly.

* m4/guix.m4: New file.
* configure.ac: Use `GUIX_ASSERT_LIBGCRYPT_USABLE'.  Set and substitute
  `LIBGCRYPT_PREFIX'.
* Makefile.am (AM_DISTCHECK_CONFIGURE_FLAGS): Pass
  `--with-libgcrypt-prefix=$(LIBGCRYPT_PREFIX)'.