Add an option for mob arrows to be "homing"

mods/ENTITIES/mcl_mobs/combat.lua

@@ -1231,6 +1231,9 @@ function mob_class:do_states_attack (dtime)
 					-- important for mcl_shields
 					ent._shooter = self.object
 					ent._saved_shooter_pos = self.object:get_pos()
+					if ent.homing then
+						ent._target = self.attack
+					end
 				end
 
 				local amount = (vec.x * vec.x + vec.y * vec.y + vec.z * vec.z) ^ 0.5

mods/ENTITIES/mcl_mobs/init.lua

@@ -350,6 +350,7 @@ function mcl_mobs.register_arrow(name, def)
 		hit_node = def.hit_node,
 		hit_mob = def.hit_mob,
 		hit_object = def.hit_object,
+		homing = def.homing,
 		drop = def.drop or false, -- drops arrow as registered item when true
 		collisionbox = {0, 0, 0, 0, 0, 0}, -- remove box around arrows
 		timer = 0,
@@ -422,6 +423,17 @@ function mcl_mobs.register_arrow(name, def)
 				end
 			end
 
+			if self.homing and self._target then
+				local p = self._target:get_pos()
+				if p then
+					if minetest.line_of_sight(self.object:get_pos(), p) then
+						self.object:set_velocity(vector.direction(self.object:get_pos(), p) * self.velocity)
+					end
+				else
+					self.target = nil
+				end
+			end
+
 			if self.hit_player or self.hit_mob or self.hit_object then
 
 				for _,player in pairs(minetest.get_objects_inside_radius(pos, 1.5)) do