Merge branch 'ar/maint-mksnpath' into HEAD

* ar/maint-mksnpath:
  Fix potentially dangerous uses of mkpath and git_path
  Fix mkpath abuse in dwim_ref and dwim_log of sha1_name.c
  Add mksnpath which allows you to specify the output buffer

diff --cc builtin-apply.c
Simple merge

diff --cc cache.h
Simple merge

diff --cc sha1_name.c
Simple merge