* gnu/services.scm (<service>)[activate]: New field.
* gnu/system.scm (operating-system-activation-script)[service-activations]:
  New procedure.  Use it, and primitive-load each activation.

* guix/build/install.scm (directives): Add /var/empty.

* gnu/system.scm (operating-system-activation-script): New procedure,
  containing most of the former 'operating-system-boot-script'.
  (operating-system-boot-script): Call it, and 'primitive-load' its
  result.
* guix/build/activation.scm (%booted-system): Remove.
  (activate-current-system): Remove #:boot? parameter and related code.

* gnu/packages/compression.scm (lzop): New variable.

* gnu/system/linux-initrd.scm (qemu-initrd): Add #:qemu-networking?
  parameter and honor it.
* gnu/system/vm.scm (system-disk-image): Pass #:qemu-networking #f.

* guix/build/download.scm (open-connection-for-uri): Remove call to
  'setsockopt'.
* guix/http-client.scm (open-socket-for-uri)[rmem-max, buffer-size]: New
  variables.  Add call to 'setsockopt'.

* guix/scripts/system.scm (show-help): Add 'disk-image'.
  (guix-system)[parse-options]: Support 'disk-image' action.
  [option-arguments]: Likewise.
  Handle the 'disk-image' action.
* doc/guix.texi (Invoking guix system): Document 'disk-image'.

* gnu/system/vm.scm (system-disk-image): New procedure.

* gnu.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* build-aux/hydra/demo-os.scm: Use (gnu) and strip import list
  accordingly.
* doc/guix.texi (Using the Configuration System): Adjust example
  accordingly.

* guix/build/vm.scm (load-in-linux-vm): When MAKE-DISK-IMAGE?, use
  '-drive ...,if=virtio' for better performance.
* gnu/system/vm.scm (qemu-image): Use /dev/vda instead of /dev/sda.

* guix/build/vm.scm (load-in-linux-vm): Add #:disk-image-format
  parameter; add 'image-file' variable.  Honor DISK-IMAGE-FORMAT.
* gnu/system/vm.scm (expression->derivation-in-linux-vm): Add
  #:disk-image-format parameter, and honor it.
  (qemu-image): Likewise.

* guix/build/linux-initrd.scm (make-essential-device-nodes): Build
  /dev/loop[0-7].

* gnu/packages/imagemagick.scm (imagemagick): Upgrade to 6.8.9-0.

* gnu/packages/perl.scm (perl-io-tty): Upgrade to 1.11.

* guix/download.scm (%mirrors)[imagemagick]: Update and add the legacy
    subdirectory of the main site as a last resort.

Reported by Manolis Ragkousis <manolis837@gmail.com>.
Fixes a regression introduced in 14af289e.

Before this commit, ./configure would leave LIBGCRYPT_PREFIX and
LIBGCRYPT_LIBDIR undefined, leading to LIBGCRYPT_LIBS="-L -lgcrypt" and
thus to a link failure.

* configure.ac: Make sure $LIBGCRYPT_PREFIX and $LIBGCRYPT_LIBDIR are
  never empty.

* guix/build/install.scm (install-grub): Call 'error' if 'system*'
  returns non-zero.
* guix/build/vm.scm (initialize-partition-table): Make 'partition-size'
  a positional parameter.  Call 'error' when 'system*' returns
  non-zero'.
  (format-partition, initialize-root-partition): New procedures.
  (initialize-hard-disk): Use them.

* guix/build/vm.scm (load-in-linux-vm): Remove misleading comment.

* gnu/packages/admin.scm (wpa-supplicant): New variable.

This allows progress reports emitted by 'substitute-binary' to be
correctly displayed.

* guix/store.scm (%newlines): New variable.
  (process-stderr) <%stderr-next>: Flush (current-build-output-port)
  when S contains one of %NEWLINES.

* guix.scm (%public-modules): Add 'monads' and 'gexp'.

This fixes a circular dependency between (gnu system) and (gnu system
linux-initrd), where the latter could end up being compiled before
'file-system-type' was defined as a macro.

* gnu/system.scm (<file-system>, %fuse-control-file-system,
  %binary-format-file-system): Move to...
* gnu/system/file-systems.scm: ... here.  New file.
* build-aux/hydra/demo-os.scm, gnu/system/linux-initrd.scm,
  gnu/system/vm.scm: Use it.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

* guix/build/linux-initrd.scm (boot-system): Add pre-unwind handler in
  'catch' form around 'primitive-load', and call 'format' and
  'display-backtrace' from there.

Regression introduced in e38e18ff.

* guix/build/vm.scm (initialize-hard-disk)[partition]: Use a string.

* gnu/packages/ccache.scm: New file.
* gnu/packages/patches/ccache-stdc-predef-test.patch: New patch.
* gnu-system.am (GNU_SYSTEM_MODULES): Add ccache.scm.
  (dist_patch_DATA): Add patch.

* gnu/packages/maths.scm (petsc) [synopsis]: Shorten.
  (petsc-complex,petsc-openmpi,petsc-complex-openmpi) [synopsis]:
  Repeat synopsis from petsc package with extensions.  [description]: Remove.

* gnu/packages/mail.scm (offlineimap) [license]: Change to gpl2+.

* gnu/packages/mail.scm (mu): New variable.

* gnu/packages/mail.scm (offlineimap): New variable.

* gnu/packages/linux.scm (kbd): New variable.

* guix/ui.scm (show-what-to-build)[built-or-substitutable?]: New
  procedure.  Check whether OUT is #f.
  Use it.
* tests/ui.scm ("show-what-to-build, zero outputs"): New test.

* guix/scripts/system.scm (install): Check whether TARGET is / and warn.

* guix/scripts/system.scm (copy-closure): New procedure.
  (install): Use it.

* doc/guix.texi (Using the Configuration System): Add 'bootloader'
  field.

* guix/scripts/system.scm (install): Add #:grub?, #:grub.cfg, and
  #:device parameters; honor them.
  (show-help): Document '--no-grub'.
  (%options): Add '--no-grub'.
  (%default-options): Add 'install-grub?'.
  (guix-system): Honor 'install-grub?' option from OPTS.  Adjust
  'install' call accordingly.
* doc/guix.texi (Invoking guix system): Document '--no-grub'.

* guix/build/vm.scm (initialize-partition-table): Honor 'device'
  parameter.
  (initialize-hard-disk): Add 'device' parameter and honor it.
* gnu/system/vm.scm (qemu-image): Adjust accordingly.

* gnu/packages/maths.scm (superlu-dist): New variable.
* gnu/packages/patches/superlu-dist-scotchmetis.patch: New patch.
* gnu-system.am (dist_patch_DATA): Add it.

* gnu/packages/maths.scm (pt-scotch): New variable.

* gnu/packages/maths.scm (scotch): New variable.
* gnu/packages/patches/scotch-test-threading.patch: New patch.
* gnu-system.am (dist_patch_DATA): Add it.

* guix/licenses.scm (cecill-c): New variable.