> With -D option diff makes `#ifdef' format output with conditional
> preprocessor directives. Currently diff-mode.el uses hard-coded
> font-lock-string-face to highlight them. The patch adds a new face
> to allow users to configure it. By default, it inherits from
The "^#.*" pattern is meant to match "comment lines". These are part of an
extension of the diff format. It has nothing to do with the -D option
which I do not consider as outputting a diff format and diff-mode does not
support this output format in any way.