compare_overlays 3277 src/buffer.c       qsort (sortvec, noverlays, sizeof (struct sortvec), compare_overlays);
compare_overlays 1744 src/buffer.h   int compare_overlays (const void *v1, const void *v2);
compare_overlays  658 src/textprop.c           if (! result || (compare_overlays (result, this) < 0))