branch master updated (6ab59cf -> b3011db)

[guix-commits]

civodul pushed a change to branch master
in repository guix.

      from  6ab59cf   gnu: emacs-org-contrib: Update to 20191226.
       new  1e43ab2   Add 'build-aux/git-authenticate.scm'.
       new  785af04   git: 'commit-difference' takes a list of excluded commits.
       new  787766e   git-authenticate: Keep a local cache of 
previously-authenticated commits.
       new  b3011db   doc: Mention "make authenticate".

The 4 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:
 Makefile.am                    |  15 +-
 build-aux/git-authenticate.scm | 410 +++++++++++++++++++++++++++++++++++++++++
 doc/contributing.texi          |  42 +++++
 guix/git.scm                   |  14 +-
 tests/git.scm                  |  26 +++
 5 files changed, 500 insertions(+), 7 deletions(-)
 create mode 100644 build-aux/git-authenticate.scm