guix package: Add optional argument to --search-paths.

* guix/scripts/package.scm (search-path-environment-variables): Add #:kind
  parameter.  Pass it to 'environment-variable-definition'.
  (display-search-paths): Add #:kind parameter and pass it to
  'search-path-environment-variables'.
  (%options): Add an optional parameter for "--search-paths".
  (guix-package)[process-query]: Handle it.
* tests/guix-package-net.sh: Adjust existing test.
* tests/guix-package.sh: Adjust existing tests and add new test.
* doc/guix.texi (Invoking guix package): Document it.

guix package: --search-paths mentions $PATH.

* guix/scripts/package.scm (search-path-environment-variables): Add $PATH to
  SEARCH-PATHS.

search-paths: 'evaluate-search-paths' can be passed a list of directories.

* guix/search-paths.scm (evaluate-search-paths): Change 'directory' to
  'directories', and adjust 'search-path-as-list' accordingly.
* guix/scripts/package.scm (search-path-environment-variables): Adjust
  call accordingly.

search-paths: 'evaluate-search-paths' now returns spec/value pairs.

* guix/search-paths.scm (evaluate-search-paths): Return
  specification/value pairs instead of variable/value pairs.
* guix/scripts/package.scm (search-path-environment-variables): Adjust
  accordingly.  Pass #:separator to 'environment-variable-definition'.

search-paths: Add 'environment-variable-definition'.

* guix/search-paths.scm (environment-variable-definition): New variable.
* guix/scripts/package.scm (search-path-environment-variables): Use it.

search-paths: Add 'evaluate-search-paths', from (guix scripts package).

* guix/scripts/package.scm (with-null-error-port,
  evaluate-search-paths): Move to...
* guix/search-paths.scm: ... here.
* guix/utils.scm (string-tokenize*): Move to...
* guix/search-paths.scm: ... here.
* tests/utils.scm ("string-tokenize*"): Adjust accordingly.

Move search path specifications to (guix search-paths).

* guix/packages.scm (<search-path-specification>,
  search-path-specification->sexp, sexp->search-path-specification):
  Move to...
* guix/search-paths.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.
* guix/build-system/cmake.scm, guix/build-system/glib-or-gtk.scm,
  guix/build-system/gnu.scm, guix/build-system/haskell.scm,
  guix/build-system/perl.scm, guix/build-system/python.scm,
  guix/build-system/ruby.scm, guix/build-system/waf.scm,
  guix/profiles.scm, guix/scripts/package.scm: Use it.

guix package: Introduce 'evaluate-search-paths'.

* guix/scripts/package.scm (evaluate-search-paths): New procedure, with
  most of the code formerly in 'search-path-environment-variables'.
  (search-path-environment-variables): Use it.

guix package: Move profile cleaning out of 'search-path-environment-variables'.

* guix/scripts/package.scm (user-friendly-profile): New procedure.
  (search-path-environment-variables): Remove 'profile' local variable.
  (display-search-paths): Explicitly call 'user-friendly-profile' for
  the argument to 'search-path-environment-variables'.
  (guix-package)[process-query]: Likewise.

profiles: Store search paths in manifests.

Discussed in <http://bugs.gnu.org/20255>.

* guix/packages.scm (sexp->search-path-specification): New variable.
* guix/profiles.scm (<manifest-entry>)[search-paths]: New field.
  (package->manifest-entry): Initialize it.
  (manifest->gexp): Match it.  Wrap #$deps in (propagated-inputs ...).
  Emit (search-paths ...).  Increment version.
  (find-package): New procedure.
  (sexp->manifest)[infer-search-paths]: New procedure.
  Use it to initialize the 'search-paths' field for versions 0 and 1.
  Add case for version 2.
* guix/scripts/package.scm (search-path-environment-variables)[manifest-entry->package]:
  Remove.
  Use 'manifest-entry-search-paths' instead of 'manifest-entry->package'
  plus 'package-native-search-paths'.
* tests/profiles.scm ("profile-manifest, search-paths"): New test.

guix package: Fix 'readlink*' implementation.

* guix/scripts/package.scm (readlink*): Fix to handle symlinks with
  relative targets.  Taken from ld-wrapper2.in.

guix package: -A and -s take supported systems into account.

* guix/scripts/package.scm (guix-package)[process-query]
  <list-available>: Restrict results to packages matching
  'supported-package?".
* guix/ui.scm (package->recutils): Print "systems:".
* tests/guix-package.sh: Add tests.
* doc/guix.texi (Invoking guix package): Adjust description of
  '--list-available' accordingly.

Merge branch 'master' into core-updates

Conflicts:
	gnu-system.am
	gnu/packages/gstreamer.scm

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.

guix package: Add '--do-not-upgrade' option.

* guix/scripts/package.scm (%options): Add the '--do-not-upgrade' option.
  (show-help): Document it.
  (options->installable): Add 'do-not-upgrade-regexps' variable.
  Use it in 'packages-to-upgrade'.
* doc/guix.texi (Invoking guix package): Document the '--do-not-upgrade'
  option.

Merge branch 'master' into core-updates

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.

Merge branch 'master' into core-updates

guix package: Avoid 'exit' calls in 'delete-matching-generations'.

* guix/scripts/package.scm (delete-matching-generations): Remove call to
  'exit' when PATTERN is "0".  Call 'leave' instead of 'exit'
  when (null-list? number).

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.