build: Make sure scripts know where to find their modules.

* guix-build.in, guix-download.in: Define `prefix' and `datarootdir', so
  that `guilemoduledir' expands to something meaningful.

release.nix: Pre-download the Guile bootstrap tarball.

* release.nix (bootstrap_guile): New variable.
  (build)[preBuild]: New attribute.

build: Fix out-of-source-tree builds.

* 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):
  Make the target's parent directory.
* pre-inst-env.in (DISTRO_BOOTSTRAP_PATH): Add the builddir-relative
  directory.

distro: Change $DISTRO_{PATCH,BOOTSTRAP}_DIRECTORY to search paths.

* distro.scm (not-colon): New variable.
  (%patch-directory): Rename to...
  (%patch-path): ... this.  Turn into a list.  Expect $DISTRO_PATCH_PATH
  to be a colon-separated search path.
  (%bootstrap-binaries-directory): Rename to...
  (%bootstrap-binaries-path): ... this.  Likewise.
  (search-patch, search-bootstrap-binary): Adjust accordingly.

* pre-inst-env.in: Change to use `DISTRO_PATCH_PATH' and
  `DISTRO_BOOTSTRAP_PATH'.

release.nix: Set succeed-on-failure and build-out-source-tree.

* release.nix: Define `succeedOnFailure', `keepBuildDirectory', and
  `buildOutOfSourceTree'.
  (build): Inherit them.

build: Move `distro/patches' to `distro/packages/patches'.

* distro/patches: Move directory to...
* distro/packages/patches: ... here.
* Makefile.am (dist_patch_DATA): Adjust accordingly.
* pre-inst-env.in (DISTRO_PATCH_DIRECTORY): Likewise.

build: Use `pre-inst-env' to compile the source.

* Makefile.am (.scm.go): Use `pre-inst-env' instead of re-defining the
  environment variables, except for `DISTRO_INSTALLED_PATCH_DIRECTORY'
  and `DISTRO_INSTALLED_BOOTSTRAP_DIRECTORY'.

guix-build: Gracefully handle `&package-input-error' conditions.

* guix/packages.scm: Export `package-error?' and `package-input-error?'.
* guix-build.in (guix-build): Catch `&package-input-error' conditions,
  print a human-readable message, and exit.

location: Start column numbers at 1.

* guix/utils.scm (source-properties->location): Use COL + 1.

distro: Add i686-linux port.

* distro/packages/bootstrap/i686-linux/bash,
  distro/packages/bootstrap/i686-linux/mkdir,
  distro/packages/bootstrap/i686-linux/tar,
  distro/packages/bootstrap/i686-linux/xz: New files.

* distro/packages/base.scm (%bootstrap-coreutils&co,
  %bootstrap-binutils, %bootstrap-glibc, %bootstrap-gcc): Add hashes of
  the i686-linux tarballs.

* Makefile.am (bootstrap_i686_linuxdir, dist_bootstrap_i686_linux_DATA,
  nodist_bootstrap_i686_linux_DATA): New variables
  (DISTCLEANFILES): Add $(nodist_bootstrap_i686_linux_DATA).
  (distro/packages/bootstrap/i686-linux/guile-bootstrap-2.0.6.tar.xz):
  New rule.

distro: gcc: Adjust to support non-x86_64 architectures.

* distro/packages/base.scm (gcc-4.7)[arguments]: In the `pre-configure'
  phase, patch all the relevant gcc/config files, not just those for
  x86_64-linux-gnu.

utils: Remove special `substitute*' syntax for lists of files.

* guix/build/utils.scm (substitute*): Remove special syntax for
  list-of-files; instead, check whether FILE is `list?' at run time.

* distro/packages/base.scm (gcc-4.7, %binutils-static): Adjust
  accordingly.

doc: Add `HACKING'.

* HACKING: New file.
* Makefile.am (EXTRA_DIST): Add it.

Add a `system' parameter to `nixpkgs-derivation'.

* guix/utils.scm (nixpkgs-derivation): Add a `system' parameter.  Pass
  it in the `nix-instantiate' invocation.

packages: Pass `system' around.

* guix/packages.scm (package-source-derivation): Add `system'
  parameter.  Pass it to METHOD.
  (package-derivation)[expand-input]: Pass SYSTEM to
  `package-derivation' and `package-source-derivation'.

* distro/packages/base.scm (package-with-bootstrap-guile)[boot]: Pass
  SYSTEM to FETCH.

derivations: Make sure `build-expression->derivation' & co. pass `system'.

* guix/derivations.scm (imported-files): Call
  `build-expression->derivation' with SYSTEM, not (%current-system).
  (build-expression->derivation): Pass SYSTEM to `imported-modules' and
  `compiled-modules'.

derivations: Pass the derivation of guile-for-build to `imported-files' & co.

* guix/derivations.scm (%guile-for-build): Initialize to #f.
  (imported-files, imported-modules, compiled-modules): Add `guile'
  keyword parameter.  Pass it down to `build-expression->derivation'.
  (build-expression->derivation)[guile-drv]: New variable.  Pass it as
  the #:guile parameter for `imported-modules' and `compiled-modules'.

* tests/derivations.scm: Set %GUILE-FOR-BUILD to the derivation of
  %BOOTSTRAP-GUILE.

distro: Build the final inputs against the final Bash, not the bootstrap Bash.

* distro/packages/base.scm (%boot4-inputs): New variable.
  (guile-final): Use it.
  (%final-inputs): Build with %BOOT4-INPUTS, not %BOOT3-INPUTS.

distro: ncurses: Don't patch shebangs.

* distro/packages/base.scm (ncurses): Pass #:patch-shebangs? #f.

distro: Bootstrap using our own binaries instead of those from Nixpkgs.

* distro/packages/base.scm (%bootstrap-inputs): Switch to using our own
  bootstrap binaries instead of those from Nixpkgs.