"kompare". Any other value is treated as a custom diff tool,
and there must be a corresponding `difftool.<tool>.cmd`
option.
+
+diff.algorithm::
+ Choose a diff algorithm. The variants are as follows:
++
+--
+`default`, `myers`;;
+ The basic greedy diff algorithm. Currently, this is the default.
+`minimal`;;
+ Spend extra time to make sure the smallest possible diff is
+ produced.
+`patience`;;
+ Use "patience diff" algorithm when generating patches.
+`histogram`;;
+ This algorithm extends the patience algorithm to "support
+ low-occurrence common elements".
+--
++