package: Add --manifest option.

* guix/scripts/package.scm (show-help): Add help text.
  (%options): Add manifest option.
  (guix-package): Add manifest option handler.
* doc/guix.texi ("Invoking guix package"): Document it.
* tests/guix-package.sh: Add test.

ui: Factorize user-provided Scheme file loading.

* guix/ui.scm (make-user-module, load*): New procedures.
* guix/scripts/system.scm (%user-module): Define in terms of
  'make-user-module'.
  (read-operating-system): Define in terms of load*'.

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.

guix gc: Add '--optimize'.

* guix/scripts/gc.scm (show-help, %options): Add --optimize.
  (guix-gc): Handle it.

publish: Add '--listen'.

* guix/scripts/publish.scm (show-help, %options): Add --listen.
  (getaddrinfo*): New procedure.
  (%default-options): Add 'address'.
  (open-server-socket): Replace 'addr' and 'port' with 'address', a
  sockaddr.
  (guix-publish): Adjust accordingly.  Augment "publishing" message with
  the actual address.
* doc/guix.texi (Invoking guix publish): Document it.

publish: Add '--user' option.

* guix/scripts/publish.scm (show-help): Add --user.
  (%options): Likewise.
  (run-publish-server): Change 'port' parameter to 'socket'.  Pass
  #:socket instead of #:addr and #:port to 'run-server'.  Update caller
  accordingly.
  (open-server-socket, gather-user-privileges): New procedures.
  (guix-publish): Use them.  Force %PRIVATE-KEY and %PUBLIC-KEY early
  on.  Warn when running as root.
* doc/guix.texi (Invoking guix publish): Document --user.

Remove assorted Guile 2.0.5 workarounds.

* guix/scripts/authenticate.scm (%default-port-conversion-strategy):
  Remove.
* guix/scripts/substitute.scm (fetch): Remove 2.0.5 special cases.
* guix/serialization.scm (write-file): Remove 'scandir' workaround.
* guix/ui.scm (command-files): Likewise.

download: Work around Guile small-receive-buffer bug.

Previously, code using directly (guix build download) was still affected
by <http://bugs.gnu.org/15368>.  This includes source derivations, the
'guix download' command, and (guix gnu-maintenance).

'guix substitute' was unaffected since it used (guix http-client), which
already had the fix.

* guix/http-client.scm (open-socket-for-uri): Remove.
  (http-fetch): Remove #:buffered? argument to 'open-socket-for-uri';
  use 'setvbuf' instead.
* guix/scripts/substitute.scm (fetch): Likewise.
* guix/build/download.scm (open-socket-for-uri): New procedure, taken
  from guix/http-client.scm, but without the #:buffered? parameter.

environment: Move iteration outside of 'for-each-search-path'.

* guix/search-paths.scm (search-path-definition): New procedure.
* guix/scripts/environment.scm (for-each-search-path): Rename to...
  (evaluate-input-search-paths): ... this.  Remove 'proc' and 'pure?'
  parameters, and return directly the list of search-path/value pairs.
  (create-environment): Use 'for-each' and 'evaluate-input-search-paths'
  instead of 'for-each-search-path'.
  (show-search-paths): Use 'for-each', 'search-path-definition', and
  'evaluate-search-paths' instead of 'for-each-search-path'.

environment: Use 'evaluate-search-paths'.

This allows 'guix environment' to correctly handle non-directory
and/or pattern search-path specifications, such as that for
'XML_CATALOG_FILES'.

* guix/scripts/environment.scm (for-each-search-path): Use
  'evaluate-search-paths' instead of 'search-path-as-list' & co.

search-paths: Define the 'PATH' environment variable.

* guix/search-paths.scm ($PATH): New variable.
* guix/scripts/environment.scm (for-each-search-path): Use it.

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.

environment: Use (guix search-paths).

* guix/scripts/environment.scm: Use (guix search-paths).  Fixes a
  regression introduced in e89431b.

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.

substitute: Increase TTL from 24h to 36h.

* guix/scripts/substitute.scm (%narinfo-ttl): Increase to 36h.

guix: build: Fix indentation for --sources in help output.

* guix/scripts/build.scm (show-help)[--sources]: Make indentation
  consistent with other long options.