branch master updated (f4dc22b -> 8074b33)

[Ludovic Courtès]

civodul pushed a change to branch master
in repository guix.

      from  f4dc22b   gnu: nmap: Update to 7.31.
       new  3382bfe   system: Avoid using device paths in <menu-entry> device 
field.
       new  9008deb   profiles: Extract a procedure for getting relative 
generation numbers.
       new  45e39ee   system: Rename previous-grub-entries to 
profile-grub-entries.
       new  aff7280   system: Optionally limit the entries returned by 
profile-grub-entries.
       new  1e17a2d   install: Extract procedure: install-grub-config.
       new  8074b33   system: Add 'guix system' actions: switch-generation and 
roll-back.

The 6 revisions listed above as "new" are entirely new to this
repository and will be described in separate emails.  The revisions
listed as "adds" were already present in the repository and have only
been added to this reference.


Summary of changes:
 doc/guix.texi            |   51 +++++++++++++++++++++-
 gnu/build/install.scm    |   23 ++++++----
 gnu/system.scm           |   22 +++++++---
 guix/profiles.scm        |   19 +++++++++
 guix/scripts/package.scm |    8 +---
 guix/scripts/system.scm  |  106 +++++++++++++++++++++++++++++++++++++++++-----
 6 files changed, 196 insertions(+), 33 deletions(-)