Problem:    Filler lines are incorrect for other window in diff mode after
            making a change.
Solution:   Copy filler lines from the current window. (closes vim/vim#8809)
https://github.com/vim/vim/commit/841c225b9ef8c5bdf5e02968a0bd62521fff6ca8

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

Port VimL's method call syntax - vim-patch:8.1.{1638,1800,1803,1807,1809,1816,1820,1821,1828,1834,1835,1861,1863,1878,1879,1888,1909,1911,1912}

Problem:    'cursorline' should not apply to 'breakindent'.
Solution:   Make 'cursorline' apply to 'breakindent' and 'showbreak'
            consistently. (closes vim/vim#8684)
https://github.com/vim/vim/commit/4f33bc20d7d5444e44d13f954e8219ad1abd26ef

Cannot be fully ported as chdir() hasn't been ported yet.

Problem:    More functions can be used as a method.
Solution:   Add has_key(), split(), str2list(), etc.
https://github.com/vim/vim/commit/a74e4946de074d2916e3d6004f7fa1810d12dda9

Problem:    Diff and cursorcolumn highlighting don't mix.
Solution:   Fix condition for what attribute to use. (Christian Brabandt,
            closes vim/vim#7258, closes vim/vim#7260)
https://github.com/vim/vim/commit/fabc3ca896751277f18a3a68e5661179728db3ad

Problem:    Unified diff fails if actually used.
Solution:   Invoke :diffupdate in the test.  Fix the check for working external
            diff. (Ghjuvan Lacambre, Christian Brabandt, closes vim/vim#8197)
https://github.com/vim/vim/commit/ad5c178a191cf2cf37a27c2a789d7afda3879831

Problem:    Using unified diff is not tested.
Solution:   Test all cases also with unified diff. (issue vim/vim#8197)
https://github.com/vim/vim/commit/485b62710004431a16feb4eb861365d082304a08