gnu: python: Set SOURCE_DATE_EPOCH to 1 instead of 0.

* gnu/packages/python.scm (python-2)[arguments]: Set SOURCE_DATE_EPOCH
  to 1 to match what the daemon does.
* guix/build/python-build-system.scm (set-SOURCE-DATE-EPOCH): Likewise.

gnu: python-2: Honor 'SOURCE_DATE_EPOCH'.

* gnu/packages/patches/python-2.7-source-date-epoch.patch: New file.
* gnu/packages/python.scm (python-2)[source]: Use it.
  [arguments]: Set SOURCE_DATE_EPOCH in 'patch-lib-shells' phase.
* guix/build/python-build-system.scm (set-SOURCE-DATE-EPOCH): New
  procedure.
  (%standard-phases): Add it.
* gnu-system.am (dist_patch_DATA): Add patch.

graft: Graft files in parallel.

* guix/build/graft.scm (rewrite-directory): Use 'n-par-for-each' instead
  of 'for-each'.

graft: Graft files in a deterministic order.

* guix/build/graft.scm (rewrite-directory)[rewrite-leaf]: Change to take
  a single parameter.  Add call to 'lstat'.  Factorize result of
  'destination'.
  Use 'find-files' instead of 'file-system-fold'.

download: Always use AI_ADDRCONFIG when resolving host names.

* guix/build/download.scm (open-socket-for-uri): Always pass
  AI_ADDRCONFIG to 'getaddrinfo' as recommended in the fine Guile
  manual.
* guix/ftp-client.scm (ftp-open): Ditto.

download: Add timeout parameter for connections.

* guix/build/download.scm (ensure-uri): New procedure.
(current-http-proxy): New variable.
(open-socket-for-uri): Copy from Guile commit aaea5b2, but add #:timeout
parameter and use 'connect*' instead of 'connect'.
(open-connection-for-uri): Add #:timeout parameter and pass it to
'open-socket-for-uri'.

Merge branch 'master' into dbus-update

build-system/haskell: CONFIG_SHELL env variable.

For Cabal packages with "build-type: Configure", a configure shell
script is run to set up build parameters.  These scripts need the
CONFIG_SHELL environment variable to be set to function properly.

* guix/build/haskell-build-system.scm (configure): Set CONFIG_SHELL if
  necessary.

Merge branch 'master' into dbus-update

syscalls: Fix ABI mismatch for 'clone'.

Fixes <http://bugs.gnu.org/21694>.

* guix/build/syscalls.scm (clone): Change 'syscall' parameter types to
  LONG, UNSIGNED-LONG, or '*; make sure it has 6 parameters.  Adjust
  caller accordingly.

Merge branch 'core-updates'

Merge branch 'master' into core-updates

Use "normalized codesets" everywhere.

In other words, change "xx_YY.UTF-8" to "xx_YY.utf8".

* guix/profiles.scm (ca-certificate-bundle): Use "en_US.utf8" instead of
  "en_US.UTF-8".
* guix/packages.scm (patch-and-repack): Likewise.
* guix/build/gnu-build-system.scm (install-locale): Likewise.
* guix/build-system/gnu.scm (gnu-build, gnu-cross-build): Likewise.
* gnu/packages/python.scm (python-ipython): Likewise.
* gnu/packages/gawk.scm (gawk): Likewise.
* build-aux/hydra/demo-os.scm: Likewise.
* gnu/packages/guile.scm (guile-ncurses)[arguments]: Remove
  'change-locale' phase.

utils: Add 'every*'.

* guix/build/gnu-build-system.scm (every*): Move to...
* guix/build/utils.scm (every*): ... here.  New procedure.

download: Check whether HORIZONTAL ELLIPSIS can be encoded.

* guix/build/download.scm (ellipsis): New procedure.
  (store-path-abbreviation): Use it.

Merge branch 'core-updates'

Merge branch 'master' into core-updates

download: Don't abbreviate things that are not store items.

Fixes a regression introduced in a8be7b9a.

* guix/build/download.scm (store-path-abbreviation): Return STORE-PATH
  if it's not an actual store path.  Fixes an out-of-range exception
  when running tests/substitute.scm and tests/store.scm.

download: Fix some minor progress-logging regressions.

* guix/build/download.scm
  (string-pad-middle): Allow resulting padded string to overflow.
  (store-url-abbreviation): Remove unnecessary procedure.
  (progress-proc): Use BASENAME as default for parameter 'abbreviation'.
  (url-fetch): Display extra newlines for readability.

emacs-build-system: Fix 'package-name-version->elpa-name-version'.

Fixes a regression introduced in b7c7c03eb5e37fc3455e4e17b0898ffc4bca29c3.

* guix/build/emacs-build-system.scm (package-name-version->elpa-name-version):
  Remove unused 'name' binding.  Do not abuse 'strip-store-file-name' to
  remove the "emacs-" prefix, which worked before b7c7c03eb5 but not after.