* guix/hash.scm (GCRY_MD_SHA256): New macro. (sha256): Use it. (open-sha256-md, md-write, md-read, md-close, open-sha256-port, port-sha256): New procedures. * tests/hash.scm: New file. * Makefile.am (SCM_TESTS): Add it.
* guix/utils.scm (sha256): Move to... * guix/hash.scm: ... here. New file. * Makefile.am (MODULES): Add it. * guix/derivations.scm, guix/scripts/download.scm, guix/scripts/hash.scm, guix/scripts/refresh.scm, tests/base32.scm, tests/derivations.scm, tests/store.scm: Use (guix hash).