build: Remove now unnecessary dependency of downloads on guix/utils.go.

* Makefile.am (distro/packages/bootstrap/x86_64-linux/guile-bootstrap-2.0.6.tar.xz,
  distro/packages/bootstrap/i686-linux/guile-bootstrap-2.0.6.tar.xz):
  Remove dependency on guix/utils.go.

doc: Document `guix-build'.

* doc/guix.texi (Invoking guix-build): Populate.

doc: Remove unnecessary @ifinfo.

* doc/guix.texi: Remove @ifinfo around @dir{category,entry}.  Suggested
  by Karl Berry <karl@freefriends.org>.

distro: Move bootstrap tarball packages to (distro packages make-bootstrap).

* distro/packages/base.scm (binutils-final): Make public.
  (static-package, %bash-static, %static-inputs, %static-binaries,
  %binutils-static, %binutils-static-stripped, %glibc-stripped,
  %gcc-static, %gcc-stripped, %guile-static, %guile-static-stripped,
  tarball-package, %bootstrap-binaries-tarball,
  %binutils-bootstrap-tarball, %glibc-bootstrap-tarball,
  %guile-bootstrap-tarball): Move to...
* distro/packages/make-bootstrap.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.

distro: bash-final: Link with `-static-libgcc'.

* distro/packages/base.scm (bash-final): Pass through
  `static-libgcc-package'.

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

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

distro: gcc: Don't add a RUNPATH to GCC when using `-static-libgcc'.

* distro/packages/base.scm (gcc-4.7)[LIB_SPEC]: Add a `-rpath' to GCC
  only when !static and !static-libgcc.

distro: readline: Allow stripping of the libraires.

* distro/packages/readline.scm (readline)[arguments]: Add `post-install'
  phase to make libraries writable.

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.

distro: Add missing `package-with-bootstrap-guile'.

* distro/packages/base.scm (binutils-final): Add missing
  `package-with-bootstrap-guile'.

distro: recutils: Comment out optional dependencies.

* distro/packages/recutils.scm (recutils): Comment out optional
  dependencies not packaged here.

distro: Add GnuPG and companion libraries.

* distro/packages/gnupg.scm: New file.
* Makefile.am (MODULES): Add it.

distro: Add zlib.

* distro/packages/compression.scm (zlib): New variable.

distro: Add (distro packages compression).

* distro/packages/base.scm (gzip, bzip2, xz): Move to...
* distro/packages/compression.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.

distro: Add GNU Pth.

* distro/packages/pth.scm: New file.
* Makefile.am (MODULES): Add it.

distro: Add GNU gperf.

* distro/packages/gperf.scm: New file.
* Makefile.am (MODULES): Add it.
* distro/packages/guile.scm (guile-reader): Use it.

distro: Split (distro packages base) into several files.

* distro/packages/base.scm (libsigsegv, gawk, perl, m4, gmp, mpfr, mpc,
  ncurses, readline, bash, libtool, libunistring, libffi, pkg-config,
  libgc): Move to modules of their own.
  (guile-1.8, guile-2.0): Move to...
* distro/packages/guile.scm: ... here.

* distro/packages/bash.scm, distro/packages/bdw-gc.scm,
  distro/packages/gawk.scm, distro/packages/libffi.scm,
  distro/packages/libsigsegv.scm, distro/packages/libtool.scm,
  distro/packages/libunistring.scm, distro/packages/m4.scm,
  distro/packages/multiprecision.scm, distro/packages/ncurses.scm,
  distro/packages/perl.scm, distro/packages/pkg-config.scm,
  distro/packages/readline.scm: New files.

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.

distro: Go for one module per package.

The alternative, which was to use one module per category, would
probably not scale well.  First, because many packages could fall into
several categories (does GnuTLS go into "networking", "security", or
"libraries"?).  Second, because that could easily lead to circular
dependencies among modules ("security" and "networking" depend on each
other, etc.)

* distro/packages/databases.scm: Rename to...
* distro/packages/recutils.scm: ... this.
* distro/packages/typesetting.scm: Rename to...
* distro/packages/lout.scm: ... this.
* Makefile.am (MODULES): Adjust accordingly.
* po/POTFILES.in: Likewise.

doc: Add "Adding new packages" in `HACKING'.

* HACKING (Adding new packages): New section.