for modern source-control systems with a global log, it's better to
have something like "Regenerate configure".
+(4) (Added in 2014) In commit comments, and ChangLog files, it is best
+ to use ways of identifying revisions that are not dependent on a
+ particular version control system. (At time of writing Emacs is
+ about to move to its third VCS and another move in the future is
+ not impossible.) An excellent way to identify commits is by
+ quoting their summary line. Another is with an action stamp - an
+ RFC3339 date followed by ! followed by the committer's email - for
+ example, "2014-01-16T05:43:35Z!esr@thyrsus.com". Often, "my
+ previous commit" will suffice.
Followup discussion:
http://lists.gnu.org/archive/html/emacs-devel/2010-01/msg00897.html