profiles: Generalize "hooks" for 'profile-derivation'.

* guix/profiles.scm (info-dir-file): Remove (null? (manifest-entries
  manifest)) test.
  (ca-certificate-bundle): Likewise.
  (ghc-package-cache-file): Turn 'if' into 'and', and remove second
  arm.
  (%default-profile-hooks): New variable.
  (profile-derivation): Remove #:info-dir?, #:ghc-package-cache?, and
  #:ca-certificate-bundle?.  Add #:hooks.  Iterate over HOOKS.  Adjust
  'inputs' accordingly.
* guix/scripts/package.scm (guix-package): Adjust 'profile-derivation'
  call accordingly.
* tests/packages.scm ("--search-paths with pattern"): Likewise.
* tests/profiles.scm ("profile-derivation",
  "profile-derivation, inputs"): Likewise.

profiles: Generate GHC's package database cache.

* guix/profiles.scm (ghc-package-cache-file): New procedure.
  (profile-derivation): Add 'ghc-package-cache?' keyword argument.  If true
  (the default), add the result of 'ghc-package-cache-file' to 'inputs'.
* guix/scripts/package.scm (guix-package)[process-actions]: Pass
  #:ghc-package-cache? to 'profile-generation'.
* tests/packages.scm ("--search-paths with pattern"): Likewise.
* tests/profiles.scm ("profile-derivation"): Likewise.

import: Add hackage importer.

* guix/import/hackage.scm: New file.
* tests/hackage.scm: New file.

tests: Skip 'guix-package-net.sh' when prerequisites aren't met.

* tests/guix-package-net.sh: Reinstate networking and shebang test that
  inadvertently vanished in commit 57b8623.

tests: Move 'guix package' tests that require networking to a separate file.

* tests/guix-package.sh (shebang_not_too_long): Remove.
  Move everything below "if [networking + shebang_not_too_long]" to...
* tests/guix-package-net.sh: ... here.  New file.
* Makefile.am (SH_TESTS): Add it.

guix package: Never remove the current generation and warn about it.

Fixes <http://bugs.gnu.org/19978>.
Reported by taylanbayirli@gmail.com (Taylan Ulrich Bayırlı/Kammer).

* guix/scripts/package.scm (delete-matching-generations): Warn when
  CURRENT is in NUMBERS, and always remove it before calling
  'delete-generations'.
* tests/guix-package.sh: Add --switch-generation=2 invocation before
  --delete-generations=3 invocation.
  Add --delete-generations=1.. test case.

tests: Deal with 'mount-points' not returning "/".

Fixes <http://bugs.gnu.org/20261>.
Reported by Mark H Weaver <mhw@netris.org>.

* tests/syscalls.scm ("mount-points"): Check for a few other likely
  mount points in addition to "/".

scripts: Add 'publish' command.

* guix/scripts/publish.scm: New file.
* po/guix/POTFILES.in: Add it.
* tests/publish.scm: New file.
* Makefile.am (MODULES): Add script module.
  (SCM_TESTS): Add test module.
* doc/guix.texi ("Invoking guix publish"): New node.

store: Add query-path-info operation.

* guix/store.scm (<path-info>): New record type.
  (read-path-info): New procedure.
  (read-arg): Add 'path-info' syntax.
  (query-path-info): New variable.
* tests/store.scm ("query-path-info"): New test.

Add (guix build gremlin).

* guix/build/gremlin.scm, tests/gremlin.scm: New files.
* Makefile.am (MODULES): Add guix/build/gremlin.scm.
  (SCM_TESTS): Add tests/gremlin.scm.

tests: Fix module name for 'lint'.

* tests/lint.scm: Change module name to 'test-lint'.

gexp: Add 'local-file'.

* guix/gexp.scm (<local-file>): New record type.
  (local-file): New procedure.
  (local-file-compiler): New compiler.
  (gexp->sexp) <struct? thing>: Handle the case where 'lower' returns a
  file name.
  (text-file*): Update docstring.local-file doc
* tests/gexp.scm ("one local file", "gexp->derivation, local-file"): New
  tests.
* doc/guix.texi (G-Expressions): Mention local files early.  Document
  'local-file'.  Update 'text-file*' documentation.

Fix remaining references to "substitute-binary".

* nix/nix-daemon/guix-daemon.cc (main): Change substitute-binary to
  substitute.
* po/guix/POTFILES.in: Likewise.
* tests/guix-daemon.sh: Likewise.
* tests/guix-system.sh: Likewise.

substitute: Rename cache directory from "substitute-binary" to "substitute".

* guix/scripts/substitute.scm (%narinfo-cache-directory): Change
  "substitute-binary" to "substitute".
* tests/store.scm ("substitute query"): Likewise.
* tests/substitute.scm (call-with-narinfo): Likewise.

Rename 'guix substitute-binary' to 'guix substitute'.

* guix/scripts/substitute-binary.scm: Rename to...
* guix/scripts/substitute.scm: ... this.  Adjust module name, entry
  point, comments, and help string accordingly.
* nix/scripts/substitute-binary.in: Rename to...
* nix/scripts/substitute.in: ... this.
* pre-inst-env.in (NIX_SUBSTITUTERS): Adjust accordingly.
* tests/substitute-binary.scm: Rename to...
* tests/substitute.scm: ... this.  Adjust references to (guix scripts
  substitute) accordingly.
* guix/ui.scm (show-guix-help)[internal?]: Change "substitute-binary" to
  "substitute".
* Makefile.am (MODULES, SCM_TESTS): Adjust to file renames.
* daemon.am (nodist_pkglibexec_SCRIPTS): Likewise.
* config-daemon.ac: Likewise.
* guix/tests.scm (call-with-derivation-narinfo): Adjust comments and
  docstring.

derivations: Add a 'cut?' parameter to 'derivation-prerequisites'.

* guix/derivations.scm (valid-derivation-input?): New procedure.
  (derivation-prerequisites): Add 'cut?' parameter and honor it.
* tests/derivations.scm ("derivation-prerequisites and
  derivation-input-is-valid?"): New test.

gexp: Fix handling of nativeness in nested gexps.

* guix/gexp.scm (gexp-inputs): Remove 'references' parameter; add
  #:native? and honor it.
  [add-reference-inputs]: Distinguish between native gexp inputs, and
  non-native gexp inputs.  Honor 'native?' field of list inputs.
* tests/gexp.scm ("ungexp + ungexp-native, nested"): New test.

gexp: Allow <gexp-input> objects in #:allowed-references.

* guix/gexp.scm (lower-references): Add <gexp-input> case.
* tests/gexp.scm ("gexp->derivation #:allowed-references, specific
  output"): New test.

gexp: Remove special meaning of forms (PACKAGE OUTPUT) in ungexp.

* guix/gexp.scm (gexp-inputs)[add-reference-inputs]: Remove clause for
  inputs of the form (PACKAGE OUTPUT).
  (gexp->sexp)[reference->sexp]: Likewise.
* tests/gexp.scm ("input list splicing"): Change 'list' to 'gexp-input'
  for glibc:debug.
  ("text-file*"): Likewise for %bootstrap-guile:out.
  ("input list splicing + gexp-input + ungexp-native-splicing"): Remove,
  now redundant.

gexp: Export 'gexp-input' constructor.

* guix/gexp.scm (<gexp-input>)[gexp-input]: Rename to...
  [%gexp-input]: ... this.  Adjust callers accordingly.
  (gexp-input): New procedure.
  (gexp-inputs)[add-reference-inputs]: When the input is a list, check
  whether each item is already 'gexp-input?' and to not rewrap those.
  (gexp-outputs)[add-reference-output]: Likewise.
  (gexp->sexp): Likewise.
* tests/gexp.scm ("input list splicing + gexp-input +
  ungexp-native-splicing"): New test.