gnu: linux-initrd: Mount /tmp as a tmpfs.

* gnu/packages/linux-initrd.scm (gnu-system-initrd): Make sure /root/tmp
  exists; mount it as a tmpfs.

gnu: vm: Add build users.

* gnu/system/shadow.scm (guix-build-accounts): New procedure.
* gnu/system/vm.scm (system-qemu-image): Use it.  Add the "guixbuild"
  group.
* gnu/system/dmd.scm (guix-service): Add 'builder-group' parameter.
  Pass 'guix-daemon' the '--build-users-group' option.

gnu: vm: Add /etc/{services,protocols,rpc} to the image.

* gnu/system/vm.scm (system-qemu-image): Link
  /etc/{services,protocols,rpc}.  Add net-base as an input.

Run 'guix' with '--no-auto-compile'.

* scripts/guix.in: Change '-s' to '--no-auto-compile'.  This avoids
  annoying messages about auto-compilation, and avoids permission denied
  issues when running without write access in the usual places.

gnu: vm: Add a 'guest' account.

* gnu/system/vm.scm (system-qemu-image): Add a "guest" user and a
  "users" user group.  Make /home/guest.  Add /etc/group.  Update
  /etc/issue to mention it.

gnu: shadow: Add record type for user groups.

* gnu/system/shadow.scm (<user-group>): New record type.
  (group-file): New procedure.
* gnu/system/vm.scm (system-qemu-image): Use it.

gnu: shadow: Add record type for user accounts.

* gnu/system/shadow.scm (<user-account>): New record type.
  (passwd-file): Use it.
* gnu/system/vm.scm (system-qemu-image): Adjust accordingly.

gnu: Add net-base.

* gnu/packages/system.scm (net-base): New variable.

build-system/trivial: Take the 'source' field into account.

* guix/build-system/trivial.scm (trivial-build): When SOURCE is true,
  add it to INPUTS.
  (trivial-cross-build): Likewise.
* tests/packages.scm ("trivial with source"): New test.

gnu: vm: Set the default networking route.

* gnu/system/dmd.scm (static-networking-service): Add #:gateway
  parameter and honor it.
* gnu/system/vm.scm (system-qemu-image): Pass #:gateway to
  'static-networking-service'.

gnu: Add net-tools.

* gnu/packages/linux.scm (net-tools): New variable.

gnu: dmd: Download from alpha.gnu.org.

* gnu/packages/system.scm (dmd): Use the alpha.gnu.org URL.

gnu: harfbuzz: Update to 0.9.21.

* gnu/packages/gtk.scm (harfbuzz): Update to 0.9.21.

gnu: Add dvdisaster.

* gnu/packages/cdrom.scm (dvdisaster): New variable.

guix package: Add '--delete-generations'.

* guix/scripts/package.scm (switch-to-previous-generation): New function.
  (roll-back): Use the new function instead of 'switch-link'.
  (show-help): Add '--delete-generations'.
  (%options): Likewise.
  (guix-package)[process-actions]: Add 'current-generation-number',
  'display-and-delete', and 'delete-generation'.  Add support for
  '--delete-generations', and reindent the code.
* tests/guix-package.sh: Test '--delete-generations'.
* doc/guix.texi (Invoking guix-package): Document '--delete-generations'.

guix package: Add 'link-to-empty-profile'.

* guix/scripts/package.scm (link-to-empty-profile): New function.
  (roll-back): Use it.

guix package: Exit with 0 when there is nothing to list.

* guix/scripts/package.scm (guix-package)[process-query]: Exit with 0
  when there are no generations containing packages or no profiles.

gnu: xf86-input-joystick: Fix installation path.

* gnu/packages/xorg.scm (xf86-input-joystick): Fix installation path.

gnu: xf86-input-vmmouse: Fix installation path.

* gnu/packages/xorg.scm (xf86-input-vmmouse): Fix installation path.

gnu: xf86-input-synaptics: Fix installation paths.

* gnu/packages/xorg.scm (xf86-input-synaptics): Fix installation paths.