Merge branch 'sb/diff-color-moved-use-xdl-recmatch' into maint

Instead of using custom line comparison and hashing functions to implement "moved lines" coloring in the diff output, use the pair of these functions from lower-layer xdiff/ code. * sb/diff-color-moved-use-xdl-recmatch: diff.c: get rid of duplicate implementation xdiff-interface: export comparing and hashing strings