mapped-devices: Properly open RAID devices.

This fixes a type error introduced in
7f8ad82bf23b032ad6bd85bb1daa87cc83de509c, given that SOURCES is a list.

* gnu/system/mapped-devices.scm (open-raid-device): Add 'apply'
invocation.

Add missing exports.

Reported by Taylan Ulrich Bayırlı/Kammer <taylanbayirli@gmail.com>
at <https://lists.gnu.org/archive/html/guix-devel/2016-09/msg01686.html>.

* gnu/system/file-systems.scm (%tty-gid): Export.
* guix/build-system/python.scm (default-python, default-python2):
Export.

system: Don't emit a GRUB 'search' command when passed a GRUB file name.

Reported by Tomáš Čech <tcech@suse.com>
at <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=20067#26>.

* gnu/system/grub.scm (grub-root-search): Don't emit anything when FILE
is a string that does not denote an absolute file name.

system: grub.cfg uses correct file names when store is not in root partition.

Fixes <http://bugs.gnu.org/24346>.
Reported by csanchezdll@gmail.com (Carlos Sánchez de La Lama).

* guix/scripts/system.scm (previous-grub-entries): Get the initrd file
name from PARAMS.
* gnu/system.scm (operating-system-grub.cfg): Use
'operating-system-initrd-file' to retrieve the initrd file name.
* gnu/system/grub.scm (strip-mount-point): New procedure.
(grub-configuration-file)[entry->gexp]: Call 'strip-mount-point' for
LINUX and INITRD.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

services: console-font: A single service handles all the VTs.

* gnu/services/base.scm (%default-console-font): New variable.
(console-font-shepherd-services): New procedure.
(console-font-service-type): Change to use 'service-type'.
(console-font-service): Rewrite using 'simple-service'.
(%base-services): Use a single CONSOLE-FONT-SERVICE-TYPE instance.
* gnu/system/install.scm (installation-services): Likewise.

install: Use login-service.

* gnu/system/install.scm (installation-services): Use login-service.

system: grub: Allow arbitrary kernel file names in 'menu-entry'.

Fixes <http://bugs.gnu.org/20067>.
Reported by Tomáš Čech <sleep_walker@suse.cz>.

* gnu/system.scm (system-linux-image-file-name)
(operating-system-kernel-file): New procedures.
(operating-system-grub.cfg): Use 'operating-system-kernel-file' for the
'kernel' field of 'menu-entry'.
(operating-system-parameters-file): Likewise for the 'kernel' entry.
(read-boot-parameters): Adjust 'kernel' field so that it contains the
absolute file name of the image.
* gnu/system/grub.scm (grub-configuration-file)[linux-image-name]:
Remove.
[entry->gexp]: Assume LINUX is the absolute file name of the kernel
image.
* doc/guix.texi (GRUB Configuration): Add an example, and adjust
'kernel' field documentation accordingly.

gnu: Add edit warning to generated grub.cfg files

* gnu/services/grub.scm (grub-configuration-file): Add code to emit warning.

gnu: lightweight-desktop.tmpl: Fix typo.

* gnu/system/examples/lightweight-desktop.tmpl: While it is currently
unknown if Bob has a brother, it is sufficiently documented that Alice
is, in fact, Bob's sister.

system: vm: Remove -net user flag.

* gnu/system/vm.scm (common-qemu-options): Remove -net user flag.

system: Use 'source-module-closure' where needed.

* gnu/system/vm.scm (%vm-module-closure): Remove.
(expression->derivation-in-linux-vm): Use 'source-module-closure'
instead of %VM-MODULE-CLOSURE.
(qemu-image): Likewise.
* gnu/system/linux-initrd.scm (expression->initrd): Likewise.
(flat-linux-module-directory, base-initrd): Likewise.
* gnu/system/mapped-devices.scm (open-luks-device): Likewise.

Reinstate "services: elogind: Provide '%elogind-file-systems' by extension."

This reverts commit 17073dafc59d62fb8cbb8b94d61d3ecc488ac59f.

system: Do not create the home directory of "nobody".

Fixes <http://bugs.gnu.org/24275>.
Reported by John Darrington <john@darrington.wattle.id.au>.

* gnu/system/shadow.scm (%base-user-accounts):
Add (create-home-directory? #f) for "nobody".

system: Add 'create-home-directory?' field to <user-account>.

* gnu/system/shadow.scm (<user-account>)[create-home-directory?]: New
field.
(user-account->gexp): Serialize it.
* gnu/build/activation.scm (activate-users+groups)[activate-user]:
Update 'match-lambda' pattern accordingly.  Pass #:create-home? to
'ensure-user'.
(add-user, modify-user, ensure-user): Add #:create-home? parameter and
honor it.
* doc/guix.texi (User Accounts): Document it.

Revert "services: elogind: Provide '%elogind-file-systems' by extension."

This reverts commit 3cf319a3f8e23831960a0f1320122cc514188a37.

services: elogind: Provide '%elogind-file-systems' by extension.

* gnu/system/file-systems.scm (%base-file-systems): Remove
%ELOGIND-FILE-SYSTEMS.
* gnu/services/desktop.scm (elogind-service-type): Extend
FILE-SYSTEM-SERVICE-TYPE to provide %ELOGIND-FILE-SYSTEMS.

ui: Remove dependency on (gnu system file-systems).

* guix/ui.scm (specification->file-system-mapping): Move to...
* gnu/system/file-systems.scm (specification->file-system-mapping):
... here.

Merge branch 'core-updates'

Revert "Merge branch 'core-updates'"

This reverts commit 455859a50f88f625d13fc2f304111f02369b366b.

mapped-devices: raid-device-mapping: Avoid non-top-level 'use-modules'.

Fixes <http://bugs.gnu.org/24135>.
Reported by myglc2 <myglc2@gmail.com>.

* gnu/system/mapped-devices.scm (open-raid-device): Avoid non-top-level
'use-modules' form.