Merge branch 'rs/blame'

* rs/blame:
  blame: use xdi_diff_hunks(), get rid of struct patch
  add xdi_diff_hunks() for callers that only need hunk lengths
  Allow alternate "low-level" emit function from xdl_diff
  Always initialize xpparam_t to 0
  blame: inline get_patch()

diff --cc builtin-blame.c
Simple merge

diff --cc diff.c
Simple merge

diff --cc xdiff-interface.c
Simple merge