Note: Using `getxattr' on the Hurd instead of running showtrans does not
work (yet?).
* gnu/build/hurd-boot.scm (setup-translator): Use 'setxattr' instead of
invoking settrans.
* gnu/system.scm (hurd-multiboot-modules): Add --x-xattr-translator-records to
enable xattr-embedding of translators.
* gnu/build/hurd-boot.scm (make-hurd-device-nodes): Do not create
dev/{null,zero,full,random,urandom} mount points.
(passive-translator-xattr?, passive-translator-installed?, translated?,
set-translator, set-hurd-device-translators): New procedures.
(false-if-EEXIST): New macro.
(boot-hurd-system): Use them instead of running MAKEDEV.
This decouples startup of the Hurd from the "hurd" package, moving the RC
script into SYSTEM.
* gnu/packages/hurd.scm (hurd)[inputs]: Remove hurd-rc-script.
[arguments]: Do not substitute it. Update "runsystem.sh" to parse kernel
arguments and exec into --system=SYSTEM/rc.
(hurd-rc-script): Move to...
* gnu/services.scm (%hurd-rc-file): ...this new variable.
(hurd-rc-entry): New procedure.
(%hurd-startup-service): Use it in new variable.
* gnu/system.scm (hurd-default-essential-services): Use it.
