* lisp/vc/diff-mode.el (diff-prev-line-if-patch-separator):
A function to return prev. line if it has git-format-patch
separator.
(diff-end-of-hunk): Make use of
diff-prev-line-if-patch-separator
diff-buffer-type: whether a buffer is a git-diff
(define-derived-mode): set diff-buffer-type to appropriate
value (bug#37395).