Merge branch 'master' into core-updates

gnu: hurd: Add Hurd headers.

* gnu/packages/hurd.scm (hurd-headers): New variable.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

Merge branch 'master' into core-updates

Conflicts:
	gnu-system.am

gnu: hurd: Add MiG.

* gnu/packages/hurd.scm (mig): New variable.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu: Add GNU Mach headers.

* gnu/packages/hurd.scm: New file
* gnu-system.am (GNU_SYSTEM_MODULES): Add hurd.scm

Co-authored-by: Ludovic Courtès <ludo@gnu.org>
Signed-off-by: Ludovic Courtès <ludo@gnu.org>