system: Allow Linux-libre to find our 'modprobe' command.

Fixes <http://bugs.gnu.org/18525>.
Reported by Mark H Weaver <mhw@netris.org>.

* gnu/build/activation.scm (activate-modprobe): New procedure.
* gnu/system.scm (modprobe-wrapper): New procedure.
  (operating-system-activation-script): Use both.

system: Add pciutils and pciutils to '%base-packages'.

* gnu/system.scm (%base-packages): Add PCIUTILS and USBUTILS.

system: Export 'local-host-aliases'.

* gnu/system.scm (local-host-aliases): New procedure.
  (default-/etc/hosts): Use it.

system: Add Patch to '%base-packages'.

* gnu/system.scm (%base-packages): Add PATCH.

system: Add support for boot-time mapped devices.

* gnu/build/linux-boot.scm (boot-system): Add #:pre-mount parameter and
  honor it.
* gnu/system/linux-initrd.scm (base-initrd): Add #:mapped-devices
  parameter.  Add 'device-mapping-commands' variable, and use it to
  build the #:pre-mount argument of 'boot-system'.
* gnu/system.scm (mapped-device-user,
  operating-system-user-mapped-devices,
  operating-system-boot-mapped-devices): New procedures.
  (device-mapping-services): Use 'operating-system-user-mapped-devices'
  instead of 'operating-system-mapped-devices'.
  (operating-system-initrd-file): Call the initrd with #:mapped-devices.

system: Add support for swap devices.

* gnu/services/base.scm (swap-service): New procedure.
* gnu/system.scm (<operating-system>)[swap-devices]: New field.
  (swap-services): New procedure.
  (essential-services): Use it.

system: Define 'device-mapping-kind', and add a 'close' procedure.

* gnu/system/file-systems.scm (<mapped-device-type>): New record type.
  (<mapped-device>)[command]: Remove field.
  [type]: New field.
* gnu/services/base.scm (device-mapping-service): Rename 'command'
  parameter to 'open'.  Add 'close' parameter and honor it.
* gnu/system.scm (luks-device-mapping): Rename to...
  (open-luks-device): ... this.
  (close-luks-device): New procedure.
  (luks-device-mapping): New variable.
  (device-mapping-services): Get the type of MD, and pass its 'open' and
  'close' fields to 'device-mapping-service'.

Merge branch 'master' into core-updates

Conflicts:
	gnu-system.am

system: Use eudev instead of udev by default.

* gnu/system.scm (%base-packages): Change 'udev' to 'eudev'.
* gnu/services/base.scm (udev-service): Change #:udev to default to
  'eudev'.

system: Add Diffutils to '%base-packages'.

* gnu/system.scm (%base-packages): Add DIFFUTILS.

system: Add more common tools to '%base-packages'.

* gnu/system.scm (%base-packages): Add gawk, tar, gzip, bzip2, xz, lzip,
  and wireless-tools.

system: Produce a basic /etc/nsswitch.conf to honor /etc/hosts.

* gnu/system.scm (etc-directory): Produce nsswitch.conf.

system: Fix the default /etc/hosts.

* gnu/system.scm (default-/etc/hosts): Fix the alias/address order.
  Add ::1.

Merge branch 'master' into core-updates

Conflicts:
	gnu/packages/image.scm

system: Add support for Linux-style mapped devices.

* gnu/system/file-systems.scm (<mapped-device>): New record type.
* gnu/system.scm (<operating-system>)[mapped-devices]: New field.
  (luks-device-mapping): New procedure.
  (other-file-system-services)[device-mappings, requirements]: New
  procedures.  Pass #:requirements to 'file-system-service'.
  (device-mapping-services): New procedure.
  (essential-services): Use it.  Append its result to the return value.
  (operating-system-initrd-file): Add comment.
* gnu/services/base.scm (file-system-service): Add #:requirements
  parameter and honor it.
  (device-mapping-service): New procedure.
* gnu/system/linux-initrd.scm (base-initrd): Add comment.

system: Add '\w' to the default PS1.

* gnu/system.scm (etc-directory)[bashrc]: Add '\w' to PS1.

activation: Make the /bin/sh symlink at activation time.

* gnu/build/install.scm (directives): Remove "/bin/sh".
* gnu/build/activation.scm (activate-/bin/sh): New procedure.
* gnu/system.scm (operating-system-activation-script): Use it.

system: Add 'hosts-file' field.

* gnu/system.scm (<operating-system>)[hosts-file]: New field.
  (default-/etc/hosts): New procedure.
  (etc-directory): Add #:hosts-file parameter and honor it.
  (operating-system-etc-directory): Build /etc/hosts, and pass
  it as #:hosts-file to 'etc-directory'.

system: Export '%setuid-programs'.

* gnu/system.scm: Export '%setuid-programs', as documented in the
  manual.

Merge branch 'master' into core-updates