gnu: serf: Use scons-build-system.

* gnu/packages/web.scm (serf): Switch to scons-build-system.

gnu: gpick: Use scons-build-system.

* gnu/packages/image.scm (gpick): Switch to scons-build-system.

gnu: linuxdcpp: Use scons-build-system.

* gnu/packages/direct-connect.scm (linuxdcpp): Switch to scons-build-system.

build-system: Add scons-build-system.

* guix/build-system/scons.scm: New file.
* guix/build/scons-build-system.scm: New file.
* Makefile.am (MODULES): Register them.
* doc/guix.texi (Build Systems): Add scons-build-system.

gnu: scons: Update to 3.0.1.

* gnu/packages/python.scm (scons): Update to 3.0.1.
(scons-python2): New variable.

gnu: dtc: Fix build on 32 bits platforms.

* gnu/packages/bootloaders.scm (dtc)[patches]: Add dtc-32-bits-check.patch and
  dtc-format-modifier.patch to fix build and tests on 32 bits platforms.
* gnu/packages/patches/dtc-32-bits-check.patch : New file.
* gnu/packages/patches/dtc-format-modifier.patch : New file.
* gnu/local.mk (dist_patch_DATA): Add two above patches.

gnu: Update r-matrix to 1.2-12.

* gnu/packages/statistics.scm (r-matrix): Update to 1.2-12.

gnu: Update r-cluster to 2.0.6.

* gnu/packages/statistics.scm (r-cluster): Update to 2.0.6.

gnu: Update r-minimal to 3.4.3.

* gnu/packages/statistics.scm (r-minimal): Update to 3.4.3.

gnu: guix: Move 'bootstrap' phase after 'unpack'.

Suggested by Mark H Weaver <mhw@netris.org>
at <https://lists.gnu.org/archive/html/guix-devel/2017-11/msg00389.html>.

* gnu/packages/package-management.scm (guix)[arguments]: Move
'bootstrap' phase back after 'unpack'.

doc: Give the absolute file name of 'hydra.gnu.org.pub' in snippets.

* doc/guix.texi (Substitute Server Authorization): Give the absolute
file name of 'hydra.gnu.org.pub' in the snippet.

gnu: grub-efi: Disable tests on all platforms.

This is a follow-up to 56f0feb6781e3680541d7adc21d6b3b4746a33ca
and 63087721bb54a14dc04ec424474386ae98f7771b, which accidentally
enabled tests for grub-efi on other platforms.

* gnu/packages/bootloaders.scm (grub-efi)[arguments]: Override inherited
tests field and disable on all platforms.

gnu: exim: Update to 4.89.1.

* gnu/packages/mail.scm (exim): Update to 4.89.1.
[source]: Remove patches for fixed CVEs (all of them).
* gnu/packages/patches/exim-CVE-2017-16943.patch: Delete file...
* gnu/packages/patches/exim-CVE-2017-16944.patch: ...as well as this file...
* gnu/packages/patches/exim-CVE-2017-1000369.patch: ...and this file.
* gnu/local.mk (dist_patch_DATA): Remove all of them.

gnu: libgit2: Avoid dependency on cURL.

This reduces the closure size from 225 MiB to 80 MiB, while still
supporting HTTP(S) access.

* gnu/packages/version-control.scm (libgit2)[source](modules, snippet):
New fields.
[inputs]: Remove CURL; add HTTP-PARSER.

gexp: Default to 'guile-2.2' for 'program-file'.

Previously things returned by 'program-file', such as %MODPROBE-WRAPPER
in (gnu services), would refer to 'guile-final'.  This would introduce
'guile-final' in the system closure, which is otherwise absent.  By
referring to 'guile-2.2' we remove that extra Guile.

* guix/gexp.scm (default-guile): Refer to GUILE-2.2 instead of
GUILE-FINAL.

gnu: spectrwm: Fix description.

* gnu/packages/wm.scm (spectrwm)[description]: Fix typo and use @dfn.

gnu: ghc-happy: Update to 1.19.8.

* gnu/packages/haskell.scm (ghc-happy): Update to 1.19.8.
[arguments]: Delete; run all tests.

gnu: curl: Update to 7.57.0 [fixes CVE-2017-{8816,8817,8818}].

* gnu/packages/curl.scm (curl): Update replacement to 7.57.0.
(curl-7.56.1): Replace with ...
(curl-7.57.0): ... new variable.

gnu: libtorrent-rasterbar: Update to 1.1.5.

* gnu/packages/bittorrent.scm (libtorrent-rasterbar): Update to 1.1.5.

gnu: grub :Disable tests on aarch64.

* gnu/packages/bootloaders.scm (grub)[arguments]: Add aarch64 to the
architectures where the test suite is not run.