TNT: When disabled leave some useful functionality enabled

- Only remove the TNT craft recipe, tnt:tnt node and the ABM
- Leave tnt:tnt_burning available for explosions in 3rd party mods

mods/tnt/init.lua

@@ -1,10 +1,8 @@
 tnt = {}
--- Default to enabled in singleplayer and disabled in multiplayer
-local singleplayer = minetest.is_singleplayer()
-local setting = minetest.setting_getbool("enable_tnt")
-if (not singleplayer and setting ~= true) or
-		(singleplayer and setting == false) then
-	return
+-- Default to enabled when in singleplayer
+local enable_tnt = minetest.setting_getbool("enable_tnt")
+if enable_tnt == nil
+	enable_tnt = minetest.is_singleplayer()
 end
 
 -- loss probabilities array (one in X will be lost)
@@ -492,28 +490,30 @@ minetest.register_node("tnt:gunpowder_burning", {
 	end,
 })
 
-minetest.register_abm({
-	nodenames = {"group:tnt", "tnt:gunpowder"},
-	neighbors = {"fire:basic_flame", "default:lava_source", "default:lava_flowing"},
-	interval = 4,
-	chance = 1,
-	action = tnt.burn,
-})
-
 minetest.register_craft({
 	output = "tnt:gunpowder",
 	type = "shapeless",
 	recipe = {"default:coal_lump", "default:gravel"}
 })
 
-minetest.register_craft({
+if enable_tnt then
+	minetest.register_craft({
 		output = "tnt:tnt",
 		recipe = {
 			{"",           "group:wood",    ""},
 			{"group:wood", "tnt:gunpowder", "group:wood"},
 			{"",           "group:wood",    ""}
 		}
-})
+	})
+
+	minetest.register_abm({
+		nodenames = {"group:tnt", "tnt:gunpowder"},
+		neighbors = {"fire:basic_flame", "default:lava_source", "default:lava_flowing"},
+		interval = 4,
+		chance = 1,
+		action = tnt.burn,
+	})
+end
 
 function tnt.register_tnt(def)
 	local name = ""
@@ -530,6 +530,7 @@ function tnt.register_tnt(def)
 	local tnt_burning = def.tiles.burning or def.name .. "_top_burning_animated.png"
 	if not def.damage_radius then def.damage_radius = def.radius * 2 end
 
+	if enable_tnt then
 		minetest.register_node(":" .. name, {
 			description = def.description,
 			tiles = {tnt_top, tnt_bottom, tnt_side},
@@ -554,6 +555,7 @@ function tnt.register_tnt(def)
 				}
 			},
 		})
+	end
 
 	minetest.register_node(":" .. name .. "_burning", {
 		tiles = {
@@ -590,4 +592,3 @@ tnt.register_tnt({
 	description = "TNT",
 	radius = radius,
 })
-