Merge branch 'jc/maint-follow-rename-fix'

* jc/maint-follow-rename-fix:
  log: test for regression introduced in v1.7.2-rc0~103^2~2
  diff --follow: do call diffcore_std() as necessary
  diff --follow: do not waste cycles while recursing

diff --cc diff.c
Simple merge

diff --cc diff.h
Simple merge