distro: GCC: Upgrade to 4.7.2.

* distro/base.scm (gcc-4.7): Upgrade to 4.7.2.

distro: Add an `ld' wrapper, to pass missing `-rpath' flags.

* distro/ld-wrapper.scm: New file.
* Makefile.am (MODULES): Add it.

* distro/base.scm (ld-wrapper-boot3): New variable.
  (%boot3-inputs): Add LD-WRAPPER-BOOT3.
  (bash-final, guile-final, ld-wrapper): New final.
  (%final-inputs): Use BASH-FINAL; add LD-WRAPPER.
  (gcc-4.7): Remove the `-rpath' trick from the `lib' spec string.

distro: gcc: Patch `lib' spec to add `-rpath' for each `-L'.

* distro/base.scm (gcc-4.7): Patch `LIB_SPEC' to add `-rpath' for each
  `-L'.  Spec string suggested by Marc Glisse <marc.glisse@inria.fr>.
  (libtool): Add `libtool-skip-tests.patch'.

* distro/patches/libtool-skip-tests.patch: New file.
* Makefile.am (dist_patch_DATA): Add it.

Add (guix ftp) and companion modules.

* guix/ftp-client.scm, guix/ftp.scm, guix/build/ftp.scm: New files.
* Makefile.am (MODULES): Add them.

* distro/base.scm (libffi): Use `ftp-fetch'.

distro: Use our own Perl during bootstrap.

* distro/base.scm (linux-headers-boot0): Use PERL with %BOOT0-INPUTS
  instead of calling out to `nixpkgs-derivation*'.

distro: gcc: Add a RUNPATH on libc.

* distro/base.scm (gcc-4.7): Remove unnecessary "libc" input.
  Add `-rpath LIBC/lib' to `LIB_SPEC'.

distro: Add Perl.

* distro/base.scm (perl): New variable.
* distro/patches/perl-no-sys-dirs.patch: New file.
* Makefile.am (dist_patch_DATA): Add it.

distro: Bootstrap via a cross-toolchain.

This allows the final toolchain to be completely independent of
%BOOTSTRAP-INPUTS.

* distro/base.scm (glibc-dynamic-linker): New procedure.
  (gcc-4.7): Remove #:path-exclusions argument.  Check whether LIBC is
  #f before using it.
  (glibc): Remove "libc_cv_as_needed" hack.  Patch `Makeconfig' to
  remove `-lgcc_s'.
  (nix-system->gnu-triplet, boot-triplet): New variables.
  (binutils-boot0): Turn into a cross-Binutils targeting (boot-triplet
  SYSTEM).
  (gcc-boot0): Likewise.  Add configure options to make a smaller
  build.  Remove "binutils-source" from the input, and use
  BINUTILS-BOOT0 instead.
  (glibc-final): Cross-build using GCC-BOOT0 and BINUTILS-BOOT0.
  (gcc-boot0-wrapped): New variable.
  (%boot2-inputs): Use it.
  (m4-boot2, gmp-boot2, mpfr-boot2, mpc-boot2): Remove.
  (binutils-final): New variable.
  (gcc-final): Turn into a joint build with GMP/MPFR/MPC.  Use
  BINUTILS-FINAL.
  (%boot3-inputs): Adjust accordingly.
  (%boot4-inputs): Remove.
  (%final-inputs): Use %BOOT3-INPUTS.

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.

distro: Reduce the bootstrap set.

* distro/base.scm (%bootstrap-inputs): Remove `gnumake', `diffutils',
  and `findutils'.
  (gnu-make-boot0, diffutils-boot0, findutils-boot0, %boot0-inputs): New
  variables.
  (binutils-boot0, gcc-boot0, linux-headers-boot0, %boot1-inputs):
  Replace %BOOTSTRAP-INPUTS by %BOOT0-INPUTS.

  (final-inputs): Remove now unneeded call to
  `source-properties->location'.

build-system/gnu: Fix `#:path-exclusions' handling.

* guix/build/gnu-build-system.scm (set-paths)[relevant-input-directories]:
  New procedure.  Use it.  This fixes #:path-exclusions handling.

utils: Make `set-path-environment-variable' verbose.

* guix/build/utils.scm (set-path-environment-variable): Print ENV-VAR
  and its value.

distro: Bootstrap with a joint GCC/Binutils/GMP/MPFR/MPC build.

* distro/base.scm (%bootstrap-inputs): Remove GMP, MPFR, and MPC.
  (substitute-keyword-arguments): New macro.
  (gcc-boot0): Add dependency on the Binutils, GMP, MPFR, and MPC
  tarballs.  Add a `unpack-binutils&co' phase to unpack them and symlink
  them so they get built, and to patch errors in `configure'.
  (glibc-final): Use `substitute-keyword-arguments' instead of a loop.
  (gcc-final): Inherit from GCC-4.7 instead of GCC-BOOT0.

distro: gcc: Avoid retention of reference to `sed'.

* distro/base.scm (gcc-4.7)[pre-configure]: Patch fixincl.x.

distro: glibc: Assume a recent Linux kernel.

* distro/base.scm (glibc): Pass "--enable-kernel=2.6.30".

packages: Accept <origin> as package inputs.

* guix/packages.scm (package-derivation): Accept use of an <origin> as
  an input.

build-system/gnu: Relax location handling in `package-with-explicit-inputs'.

* guix/build-system/gnu.scm (package-with-explicit-inputs): Convert LOC
  when it is a source-property list.

distro: mpc: Upgrade to 1.0.

* distro/base.scm (mpc): Upgrade to 1.0.

packages: Add `package-full-name'.

* guix/packages.scm (package-full-name): New procedure.
  (package-derivation): Use it.

guix-build: Add `--derivations'.

* guix-build.in (show-help): Add `--derivations'.
  (%options): Likewise.
  (guix-build): Handle it.