Thanks to Jason Self <jself@gnu.org> for the kernel configs.
* gnu/packages/linux.scm (kernel-config): New procedure.
(linux-libre)[build-phase]: Copy it to .config. Reduce the list of
things appended to .config.
[native-inputs]: Add "kconfig" input.
* gnu/packages/linux-libre-i686.conf,
gnu/packages/linux-libre-x86_64.conf: New files, from
<http://jxself.org/x86-32.txt> and <http://jxself.org/x86-64.txt>.
* Makefile.am (KCONFIGS): New variable.
(nobase_dist_guilemodule_DATA): Add it.