uuid: 'uuid' macro supports more UUID types.

* gnu/system/uuid.scm (string->uuid): Turn 'type' into an optional
argument.
(uuid): Add clauses to allow for an optional 'type' parameter.

system: Introduce a disjoint UUID type.

Conceptually a UUID is just a bytevector.  However, there's software out
there such as GRUB that relies on the string representation of different
UUID types (e.g., the string representation of DCE UUIDs differs from
that of ISO-9660 UUIDs, even if they are actually bytevectors of the
same length).  This new <uuid> record type allows us to preserve
information about the type of UUID so we can eventually convert it to a
string using the right representation.

* gnu/system/uuid.scm (<uuid>): New record type.
(bytevector->uuid): New procedure.
(uuid): Return calls to 'make-uuid'.
(uuid->string): Rewrite using 'match-lambda*' to accept a single 'uuid?'
argument.
* gnu/bootloader/grub.scm (grub-root-search): Check for 'uuid?' instead
of 'bytevector?'.
* gnu/system.scm (bootable-kernel-arguments): Check whether ROOT-DEVICE
is 'uuid?'.
(read-boot-parameters): Use 'bytevector->uuid' when the
store device is a bytevector.
(read-boot-parameters-file): Check for 'uuid?' instead of 'bytevector?'.
(device->sexp): New procedure.
(operating-system-boot-parameters-file): Use it for 'root-device' and
'store'.
(operating-system-bootcfg): Remove conditional in definition of
'root-device'.
* gnu/system/file-systems.scm (file-system->spec): Check for 'uuid?' on
DEVICE and take its bytevector.
* gnu/system/mapped-devices.scm (open-luks-device): Likewise.
* gnu/system/vm.scm (iso9660-image): Call 'uuid-bytevector' for the
 #:volume-uuid argument.

file-systems: Introduce (gnu system uuid).

* gnu/build/file-systems.scm (sub-bytevector)
(latin1->string, %fat32-endianness, fat32-uuid->string)
(%iso9660-uuid-rx, string->iso9660-uuid)
(iso9660-uuid->string, %network-byte-order)
(dce-uuid->string, %uuid-rx, string->dce-uuid)
(string->ext2-uuid, string->ext3-uuid, string->ext4-uuid)
(vhashq, %uuid-parsers, %uuid-printers, string->uuid)
(uuid->string): Move to...
* gnu/system/uuid.scm: ... here.  New file.
* gnu/system/file-systems.scm (uuid): Move to the above file.
* gnu/system/vm.scm: Adjust accordingly.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add uuid.scm.

install: Add OpenSSH to the global profile.

Suggested by Jan Nieuwenhuizen.

* gnu/system/install.scm (installation-os)[packages]: Add OPENSSH.

install: Add 'passwd' to $PATH.

Suggested by Jan Nieuwenhuizen.

* gnu/system/install.scm (installation-os)[setuid-programs]: Add 'passwd'.

vm: Call iso9660-image with #:register-closures? as #t.

* gnu/system/vm.scm (system-disk-image): Call iso9660-image with
  #:register-closures? as #t.

vm: Add support for registering closures to iso9660-image.

* gnu/system/vm.scm (iso9660-image): Add support for registering closures.

vm: Remove redundant conditional in system-disk-image.

* gnu/system/vm.scm (system-disk-image): Remove redundant conditional for
  #:file-system-type when calling qemu-image.

gnu: bootloader: Deprecate "device" field in favor of "target".

* gnu/bootloader.scm (<bootloader-configuration>): Deprecate "device" field in
favor of "target" field.  This is mostly a renaming but also a generalization
to support UEFI targets being paths to a mounted partition instead of a device
name.
* gnu/system/examples/bare-bones.tmpl:
* gnu/system/examples/desktop.tmpl:
* gnu/system/examples/lightweight-desktop.tmpl:
* gnu/system/examples/vm-image.tmpl:
* gnu/system/install.scm:
* gnu/tests.scm:
* gnu/tests/install.scm:
* gnu/tests/nfs.scm:
* tests/system.scm: Adapt all invocations of bootloader-configuration.
* guix/scripts/system.scm (perform-action): Rename device argument to
bootloader-target.
(process-action): Adapt caller.
* doc/guix.texi (Proceeding with the Installation):
* doc/guix.texi (Bootloader Configuration): Update documentation.

Merge branch 'master' into core-updates

gnu: grub-efi-bootloader: Specialize grub-install invocation.

* gnu/bootloader/grub.scm (install-grub-efi): Fix grub-install invocation for
  EFI systems.
* gnu/system/examples/bare-bones.tmpl: Use the newer
"bootloader-configuration" syntax.
* gnu/system/examples/desktop.tmpl: Use bootloader-configuration sytax.  Also,
use the same label for the LUKS-mapped device and the root partition.  Remove
unneeded "title" field for the file-system based on LUKS; as noted in the
manual, the "title" field is ignored for mapped devices.
* gnu/system/examples/lightweight-desktop.tmpl: Use bootloader-configuration,
and use grub-efi-bootloader.

Merge branch 'master' into core-updates

vm: Use grub-hybrid's grub-mkrescue.

* gnu/system/vm.scm (system-disk-image): Use grub-hybrid's grub-mkrescue.
* gnu/bootlader/grub.scm (grub-mkrescue-bootloader): New variable.

Merge branch 'master' into core-updates

system: Add 'grep --color' alias in '.bash_profile' skeleton.

* gnu/system/shadow.scm (default-skeletons)[profile]: Add 'grep' alias.

system: Add a default '.guile' skeleton.

* gnu/system/shadow.scm (default-skeletons): Add ".guile".

Merge branch 'master' into core-updates

vm: Add a <virtual-machine> type and associated gexp compiler.

* gnu/system/vm.scm (system-qemu-image/shared-store-script): Add
 #:options parameter and honor it.
(<virtual-machine>): New record type.
(virtual-machine): New macro.
(port-forwardings->qemu-options, virtual-machine-compiler): New
procedures.

vm: 'iso9660-image' produces a single-file output.

* gnu/system/vm.scm (expression->derivation-in-linux-vm): Add
  #:single-file-output? and pass it to 'load-in-linux-vm'.
(iso9660-image): Pass #:single-file-output? to
'expression->derivation-in-linux-vm'.
* gnu/build/vm.scm (load-in-linux-vm): Add #:single-file-output? and
honor it.

locale: Demonadify the locale creation API.

* gnu/system/locale.scm (single-locale-directory): Use 'computed-file'
instead of 'gexp->derivation'.
(locale-directory): Adjust accordingly and do the same.
* gnu/system.scm (operating-system-directory-base-entries): Adjust
accordingly.