* guix/derivations.scm (derivation->output-path,
derivation->output-paths): New procedures.
(derivation-path->output-path): Use 'derivation->output-path'.
(derivation-path->output-paths): Use 'derivation->output-paths'.
(derivation): Accept 'derivation?' objects as inputs. Return a single
value.
(build-derivations): New procedure.
(compiled-modules): Use 'derivation->output-paths'.
(build-expression->derivation)[source-path]: Add case for when the
input matches 'derivation?'.
[prologue]: Accept 'derivation?' objects in INPUTS.
[mod-dir, go-dir]: Use 'derivation->output-path'.
* guix/download.scm (url-fetch): Adjust to the single-value return.
* guix/packages.scm (package-output): Use 'derivation->output-path'.
* guix/scripts/build.scm (guix-build): When the argument is
'derivation-path?', pass it through 'read-derivation'.
Use 'derivation-file-name' to print out the .drv file names, and to
register them. Use 'derivation->output-path' instead of
'derivation-path->output-path'.
* guix/scripts/package.scm (roll-back): Adjust to the single-value
return.
(guix-package): Use 'derivation->output-path'.
* guix/ui.scm (show-what-to-build): Adjust to deal with 'derivation?'
objects instead of .drv file names.
* gnu/system/grub.scm (grub-configuration-file): Use
'derivation->output-path' instead of 'derivation-path->output-path'.
* gnu/system/vm.scm (qemu-image, system-qemu-image): Likewise.
* tests/builders.scm, tests/derivations.scm, tests/packages.scm,
tests/store.scm, tests/union.scm: Adjust to the new calling
convention.
* doc/guix.texi (Defining Packages, The Store, Derivations): Adjust
accordingly.
* gnu/system/vm.scm (example2): Use 'pam-services->directory'. Change
POPULATE to create /etc/pam.d, /etc/login.defs, and /var/run. Change
BOOT to spawn syslogd; boot to Bash. Add inputs.
* gnu/packages/linux.scm (<pam-service>, <pam-entry>): New record
types.
(pam-service->configuration, pam-services->directory,
unix-pam-service): New procedures.
(%pam-other-services): New variable.
* gnu/system/vm.scm (/etc/passwd): Rename to...
(passwd-file): ... this. Add 'shadow?' keyword parameter. Change
format of ACCOUNTS, and fix CONTENTS.
(example2): Adjust accordingly. Create both /etc/shadow and
/etc/passwd, the latter being used by getpwnam(3) & co. when nscd is
not running.
to compile with Python 2 instead of the default Python 3.
* guix/build-system/python.scm (default-python2, package-with-explicit-python,
package-with-python2): New procedures.
* guix/build-system/python.scm (python2-pytz, python2-babel): Use
package-with-python2.
* gnu/packages/grub.scm (<menu-entry>): New record type.
(grub-configuration-file): New procedure.
* gnu/system/vm.scm (qemu-image): Remove parameters 'linux',
'linux-arguments', and 'initrd'. Add 'grub-configuration' parameter.
Honor them, and remove grub.cfg generation code accordingly.
(example2): Use `grub-configuration-file', and adjust accordingly.
* gnu/system/vm.scm (qemu-image): Add 'populate' keyword parameter and
honor it; make it an input.
(/etc/shadow): New procedure.
(example2): Call it; build 'populate' script, and pass it to
'qemu-image'.
* gnu/system/vm.scm (qemu-image): Use (guix build linux-initrd). Remove
'mknod' calls; use 'make-essential-device-nodes' to populate /dev on
the target image.
* gnu/packages/linux-initrd.scm (qemu-initrd): When /root/dev exists,
don't call 'make-essential-device-nodes'.
