Problem:    Filler lines are wrong when changing text in diff mode.
Solution:   Don't change the filler lines on every change.  Check
            scrollbinding when updating the filler lines. (closes vim/vim#8809)
https://github.com/vim/vim/commit/04626c243c47af91c2580eaf23e12286180e0e81

Problem:    CursorLine highlight used while 'cursorline' is off.
Solution:   Check 'cursorline' is set. (cloes vim/vim#5017)
https://github.com/vim/vim/commit/49474ca12236776bb56aeb9d39bd6592e28157c7

filling lines in diff mode.

Problem:    Line numbers below filler lines not always updated.
Solution:   Don't break out of the win_line() loop too early. (Christian
            Brabandt, closes vim/vim#6294, closes vim/vim#6138)
https://github.com/vim/vim/commit/511feec6f0a9e954f1d7353425fa51232b1a8e88

Before 6e9ea5adc `win_ins_lines` would return `FAIL` for `i/line_count == 0`.

Handle this by checking it in the outer `if`.

Ref: https://github.com/neovim/neovim/commit/6e9ea5ad#commitcomment-35084669

Problem:    Extending sign and foldcolumn below the text is confusing.
Solution:   Let the sign and foldcolumn stop at the last text line, just like
            the line number column.  Also stop the command line window leader.
            (Christian Brabandt)

https://github.com/vim/vim/commit/8ee4c01b8c79a29065c1af05e5d9c0721069765f

Closes https://github.com/neovim/neovim/issues/9613

Problem:    Parsing of 'diffopt' is slightly wrong.
Solution:   Fix the parsing and add a test. (Jason Franklin, Christian
            Brabandt)

https://github.com/vim/vim/commit/b6fc72851c45a36a370f9516c68508e47b41c4c1

Problem:    Not all white space difference options available.
Solution:   Add "iblank", "iwhiteall" and "iwhiteeol" to 'diffopt'.

https://github.com/vim/vim/commit/785fc6567f572b8caefbc89ec29bbd8b801464ae