Add an `env-vars' keyword parameter to `build-expression->derivation'.

* guix/derivations.scm (build-expression->derivation): New `env-vars'
  keyword parameter; default to '().  Use it.

build-system/gnu: Add `path-exclusions' parameter.

* guix/build/gnu-build-system.scm (set-paths): Add new `path-exclusions'
  parameter; honor it.
* guix/build-system/gnu.scm (gnu-build): New `path-exclusions' keyword
  parameter; pass it to BUILDER.

* distro/base.scm (gcc-4.7): Exclude "libc" from $LIBRARY_PATH.

build-system/gnu: Honor the `patch-shebangs?' and `strip-binaries?' parameters.

* guix/build/gnu-build-system.scm (patch-shebangs): Honor
  PATCH-SHEBANGS?.
  (strip): Honor STRIP-BINARIES?.  Display a message from `strip-dir'.

build-system/gnu: Add a `strip' phase.

* guix/build/gnu-build-system.scm (strip): New procedure.
  (%standard-phases): Add it.

* guix/build-system/gnu.scm (gnu-build): New `strip-binaries?',
  `strip-flags', and `strip-directories' keyword parameters.  Pass them
  to BUILDER.

build-system/gnu: Always invoke `configure' with a relative path.

* guix/build/gnu-build-system.scm (configure): Change SRCDIR to always
  be a relative path.

define-record-type*: Add the `inherit' syntactic constructor keyword.

* guix/utils.scm (define-record-type*)[make-syntactic-constructor]: New
  `type' parameter.  Add the `inherit' keyword and corresponding support
  code.

* tests/utils.scm ("define-record-type* & inherit", "define-record-type*
  & inherit & letrec* behavior"): New tests.

utils: Change `substitute*' to accept a list of files to patch.

* guix/build/utils.scm (substitute*): Support a list of files as the
  first argument.

build-system/gnu: Add `out-of-source?' keyword parameter.

* guix/build/gnu-build-system.scm (configure): Add an `out-of-source?'
  keyword parameter; build out-of-source-tree when #t.
* guix/build-system/gnu.scm (gnu-build): Add `out-of-source?' keyword
  parameter.  Pass it in BUILDER.

packages: Raise an error condition upon invalid input.

* guix/packages.scm (&package-error, &package-input-error): New
  condition types.
  (package-derivation): Raise a `&package-input-error' when no match is
  made.

Add `close-connection'.

* guix/store.scm (close-connection): New procedure.

build-system/gnu: Augment $PATH with $out for `patch-shebangs'.

* guix/build/gnu-build-system.scm (patch-shebangs): Add BINDIRS to
  $PATH, and pass that to `patch-shebang'.

utils: Add a `path' argument to `patch-shebang'.

* guix/build/utils.scm (patch-shebang): Add an optional `path'
  parameter.  Change SHEBANG-RX to match the whole interpreter file
  name.  Don't patch when BIN and CMD are the same.  Add docstring.

build-system/gnu: Add a `patch-shebangs' phase.

* guix/build/gnu-build-system.scm (patch-shebangs): New procedure.
  (%standard-phases): Add it.

* guix/build-system/gnu.scm (gnu-build): New `patch-shebangs?' keyword
  parameter.  Pass it to the builder's `gnu-build'.

utils: Add `patch-shebang'.

* guix/build/utils.scm (search-path-as-string->list): New procedure.
  (dump-port, patch-shebang): New procedures.

build: Add `--with-libgcrypt-prefix'; capture the path to libgcrypt.

* configure.ac: Add `--with-libgcrypt-prefix'.  Substitute `LIBGCRYPT'.

* Makefile.am (.scm.go): Pass $(LIBGCRYPT).

* guix/utils.scm (%libgcrypt): New variable.
  (sha256): Use it.

packages: Add all non-derivation paths to the store.

* guix/packages.scm (package-derivation): Add all non-derivation paths
  to the store.

packages: Allow store paths as inputs.

* guix/packages.scm (package-derivation): Allow non-derivation store
  paths as inputs.

build: Pass $(NIX_INSTANTIATE) to the build and test environments.

* Makefile.am (.scm.go): Define $NIX_INSTANTIATE.
  (TESTS_ENVIRONMENT): Likewise, and define $NIX_HASH.
* guix/utils.scm (nixpkgs-derivation): Use $NIX_INSTANTIATE when
  defined.

* tests/utils.scm (%nix-hash): New variable.
  ("sha256 & bytevector->nix-base32-string"): Use it.

Add `nixpkgs-derivation*'; use it in the distro.

* guix/utils.scm (nixpkgs-derivation*): New macro.

* distro/base.scm: Use it instead of `nixpkgs-derivation'.

Unset `LD_LIBRARY_PATH' in `build-expression->derivation'.

* guix/derivations.scm (build-expression->derivation)[prolog]: Unset
  `LD_LIBRARY_PATH'.