Problem: Using an external diff program is slow and inflexible.
Solution: Include the xdiff library. (Christian Brabandt)
Use it by default.
e828b7621c
vim-patch:8.1.0360
vim-patch:8.1.0364
vim-patch:8.1.0366
vim-patch:8.1.0370
vim-patch:8.1.0377
vim-patch:8.1.0378
vim-patch:8.1.0381
vim-patch:8.1.0396
vim-patch:8.1.0432