* gnu/system.scm (etc-directory): Change default value of #:profile.
Change contents of SHELLS. Use /run/current-system/profile/{s,}bin in
BASHRC.
(operating-system-boot-script)[%modules]: Add (guix build
linux-initrd). Add call to 'activate-current-system' in gexp.
(operating-system-initrd-file, operating-system-grub.cfg): New
procedures.
(operating-system-derivation): Don't build grub.cfg here and remove it
from the file union.
* gnu/system/vm.scm (qemu-image): Remove #:populate.
(operating-system-build-gid, operating-system-default-contents):
Remove.
(system-qemu-image): Remove call to
'operating-system-default-contents'. Use 'operating-system-grub.cfg'
to get grub.cfg. Add GRUB.CFG to #:inputs.
(system-qemu-image/shared-store): Likewise, but don't add GRUB.CFG to
#:inputs.
(system-qemu-image/shared-store-script): Pass --system kernel option.
* guix/build/activation.scm (%booted-system, %current-system): New
variables.
(boot-time-system, activate-current-system): New procedures.
* guix/build/install.scm (evaluate-populate-directive): Add case
for ('directory name uid gid mode).
(directives, populate-root-file-system): New procedures.
* guix/build/vm.scm (initialize-hard-disk): Replace calls to
'evaluate-populate-directive' by a call to
'populate-root-file-system'.
* gnu/services/dmd.scm (dmd-configuration-file): Use
/run/current-system/profile/bin.
* gnu/services/xorg.scm (slim-service): Likewise.
* gnu/services.scm (<service>)[inputs]: Remove.
* gnu/system.scm (links): Remove.
(etc-directory): Add PASSWD and SHADOW to #:inputs.
(operating-system-boot-script): Pass ETC to 'dmd-configuration-file'.
(operating-system-derivation): Remove EXTRAS from the union.
* gnu/system/linux.scm (pam-service->configuration): Rewrite in terms of
'gexp->derivation'. Compute the contents on the build side. Expect
'arguments' to contain a list of gexps.
(pam-services->directory): Rewrite in terms of 'gexp->derivation'.
(unix-pam-service): Change 'arguments' to a list of one gexp.
* gnu/system/shadow.scm (<user-account>)[inputs]: Remove.
[shell]: Change default value to a gexp.
(passwd-file): Rewrite in terms of 'gexp->derivation'. Compute
contents on the build side.
* gnu/services/base.scm (host-name-service, mingetty-service,
nscd-service, syslog-service, guix-service): Change 'start' and 'stop'
to gexps; remove 'inputs' field.
(guix-build-accounts): Change 'shell' field to a gexp.
* gnu/services/networking.scm (static-networking-service): Change
'start' and 'stop' to gexps; remove 'inputs' field.
* gnu/services/xorg.scm (slim-service): Likewise.
* gnu/services/dmd.scm (dmd-configuration-file): Expect ETC to be a
derivation. Change 'config' to a gexp. Use 'gexp->file' instead of
'text-file'.
* doc/guix.texi (Defining Services): Update nscd example with gexps, and
without 'inputs'. Add xref to "G-Expressions".
