ref: 6bd7215355f1a2aa90c6166d3b2b6dae1f0711c2
dir: /sys/src/cmd/diff/test/merge5.expected/
lc: (2,1)::(2,4) rc: (4,7)::(4,7) 1 a b c lc: (5,5)::(8,8) rc: (4,7)::(4,7) 2 3 <<<<<<<<<< test/merge-t5.l 4 x 6 7 ========== original 4 5 6 7 ========== test/merge-t5.r w x y z >>>>>>>>>> 8 9 10