Add on_blast support

mods/ITEMS/mcl_tnt/init.lua

@@ -221,6 +221,12 @@ tnt.boom = function(pos, info)
 					-- TODO: Implement the real blast resistance algorithm
 					if def and n.name ~= "air" and n.name ~= "ignore" and (def._mcl_blast_resistance == nil or def._mcl_blast_resistance < 1000) then
 						activate_if_tnt(n.name, np, pos, 3)
+						-- Custom blast function defined by node.
+						-- Node removal and drops must be handled manually.
+						if def.on_blast then
+							def.on_blast(np, 1.0)
+						-- Default destruction handling: Remove nodes, drop items
+						else
 							minetest.remove_node(np)
 							core.check_for_falling(np)
 							if n.name ~= "mcl_tnt:tnt" and math.random() > 0.9 then
@@ -237,6 +243,7 @@ tnt.boom = function(pos, info)
 					end
 				end
 			end
+		end
 		add_effects(pos, range, {})
 	end
 end