* guix/derivations.scm (build-expression->derivation): Add all of INPUTS
as inputs to the final derivation.
* guix/build/gnu-build-system.scm, guix/build/utils.scm,
guix/gnu-build-system.scm: New files.
* tests/builders.scm ("gnu-build"): New test.
* guix/derivations.scm (imported-files)[builder]: For TAIL, check
whether it exists before (mkdir TAIL).
* tests/derivations.scm ("imported-files"): Add file with a common
prefix.
* guix/derivations.scm (imported-modules): New procedure.
(build-expression->derivation): New keyword argument `modules'.
Use `imported-modules' when MODULES is non-empty, and pass it with
`-L' to GUILE.
* guix/build/http.scm, guix/http.scm, tests/builders.scm: New files.
* guix/derivations.scm (imported-files): New procedure.
(build-expression->derivation): Correctly handle inputs that are
sources and not derivation paths.
* tests/derivations.scm ("imported-files"): New test.
* guix/derivations.scm (build-expression->derivation): Add `outputs'
keyword parameter; pass it to `derivation'. Define `%outputs' in the
prologue.
* tests/derivations.scm ("build-expression->derivation with two
outputs"): New test.
* guix/derivations.scm (build-expression->derivation): Pass HASH and
HASH-ALGO to `derivation'.
* tests/derivations.scm ("build-expression->derivation for fixed-output
derivation"): New test.
* guix/derivations.scm (read-derivation)[outputs->alist]: For
fixed-outputs, convert HASH with `base16-string->bytevector'.
(write-derivation): Likewise, convert HASH-ALGO to a string and HASH
to a base16 string.
(derivation-hash): Expect HASH to be a bytevector, not a string;
convert HASH with `bytevector->base16-string'.
* tests/derivations.scm ("fixed-output derivation"): New test.
* guix/derivations.scm (%guile-for-build): New parameter.
(build-expression->derivation): New procedure.
* tests/derivations.scm ("build-expression->derivation without inputs",
"build-expression->derivation with one input"): New tests.
* guix/derivations.scm (derivation-path->output-path): New procedure.
(derivation-hash): Call `memoize'. In the fixed-output case, convert
HASH-ALGO to a string. In the other case, sort inputs in the
alphabetical order of their hex hash. For inputs with no sub-drvs,
add "out" as the sub-drv.
* guix/utils.scm (%nixpkgs-directory): New parameter.
(nixpkgs-derivation, memoize): New procedures.
* tests/derivations.scm ("build derivation with 1 source"): Remove
useless shebang.
(%coreutils): New variable.
("build derivation with coreutils"): New test.
* guix/store.scm (%store-prefix): New parameter.
(store-path?, derivation-path?): New procedures.
* guix/derivations.scm (write-derivation): Pass SOURCES through
`object->string'.
(compressed-hash, store-path, output-path, derivation): New
procedures.
* tests/derivations.scm (%store): New global variable.
("derivation with no inputs"): New test.
* guix/derivations.scm: Export `read-derivation' and `write-derivation'.
* srfi/srfi-64.scm, srfi/srfi-64.upstream.scm: New files, from libchop.
* tests/derivations.scm, tests/test.drv: New files.