* gnu/system.scm (<operating-system>)[groups]: Change default to just
the 'root' group.
[sudoers]: New field.
(etc-directory): Add #:sudoers parameter. Add 'sudoers' to the
file union.
(operating-system-etc-directory): Pass #:sudoers to 'etc-directory'.
(%setuid-programs): Add 'sudo'.
(%sudoers-specification): New variable.
* gnu/system/linux.scm (base-pam-services): Add 'sudo'.
* build-aux/hydra/demo-os.scm: Add 'groups' field; add 'guest' to the
'wheel' group.
* gnu/system.scm (<operating-system>)[pam-services, setuid-programs]:
New fields.
(etc-directory)[bashrc]: Prepend /run/setuid-programs to $PATH.
(operating-system-etc-directory): Honor
'operating-system-pam-services'.
(%setuid-programs): New variable.
(operating-system-boot-script): Add (guix build utils) to the set of
imported modules. Call 'activate-setuid-programs' in boot script.
* gnu/system/linux.scm (base-pam-services): New procedure.
* guix/build/activation.scm (%setuid-directory): New variable.
(activate-setuid-programs): New procedure.
* build-aux/hydra/demo-os.scm: Add 'pam-services' field.
* build-aux/hydra/demo-os.scm: New file.
* Makefile.am (EXTRA_DIST): Add it.
* build-aux/hydra/gnu-system.scm (qemu-jobs): New procedure.
(hydra-jobs): Use it.
* guix/scripts/system.scm (read-operating-system): Export.
* build-aux/hydra/gnu-system.scm (hydra-jobs)[systems]: Define locally,
independently of ARGUMENTS. This matches the new Hydra convention,
where using a 'system' input is deprecated.
* build-aux/hydra/gnu-system.scm (package->alist): Call
'derivation-file-name' on the result of 'package-derivation'.
* build-aux/hydra/guix.scm (package->alist): Likewise.
* build-aux/hydra/guix.scm (tarball-package): Add 'nix-checkout'
parameter. Replace 'patch-bootstrap-script' phase by
'set-nix-module'.
(hydra-jobs): Get the 'nix' value from ARGUMENTS, and pass it to
'tarball-package'.
* build-aux/hydra/gnu-system.scm (%core-packages): New variable.
(%packages-to-cross-build): Make an alias for %CORE-PACKAGES.
(hydra-jobs): Check for the 'subset' argument, and honor it for values
"all" and "core".
* build-aux/hydra/gnu-system.scm (hydra-jobs): Pick all the `system'
keys in ARGUMENTS.
[cross-jobs]: Turn into a procedure, with a `system' parameter.
Build packages for all of SYSTEMS and %CROSS-TARGETS.