Merge branch 'jk/commit-date-approxidate'

* jk/commit-date-approxidate:
commit: accept more date formats for "--date"
commit: print "Date" line when the user has set date
pretty: make show_ident_date public
commit: use split_ident_line to compare author/committer

diff --cc builtin/commit.c
Simple merge

diff --cc cache.h
Simple merge