Fix some 'undeclared assignment' warnings

advtrains/advtrains/init.lua

@@ -43,6 +43,7 @@ advtrains.modpath = minetest.get_modpath("advtrains")
 function advtrains.print_concat_table(a)
 	local str=""
 	local stra=""
+	local t
 	for i=1,20 do
 		t=a[i]
 		if t==nil then

advtrains/advtrains/signals.lua

@@ -27,7 +27,6 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 			inventory_image="advtrains_retrosignal_inv.png",
 			drop="advtrains:retrosignal_off",
 			description=attrans("Lampless Signal (@1)", attrans(r..rotation)),
-			on_rightclick=switchfunc,
 			sunlight_propagates=true,
 			groups = {
 				cracky=3,
@@ -62,7 +61,6 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 			inventory_image="advtrains_signal_inv.png",
 			drop="advtrains:signal_off",
 			description=attrans("Signal (@1)", attrans(r..rotation)),
-			on_rightclick=switchfunc,
 			groups = {
 				cracky=3,
 				not_blocking_trains=1,

advtrains/advtrains/tracks.lua

@@ -154,7 +154,7 @@ ap.t_30deg_straightonly={
 	},
 	slopenodes={},
 	rotation={"", "_30", "_45", "_60"},
-	increativeinv={st},
+	increativeinv={"st"},
 }
 ap.t_30deg_straightonly_noplacer={
 	regstep=1,
@@ -179,7 +179,7 @@ ap.t_30deg_straightonly_noplacer={
 	},
 	slopenodes={},
 	rotation={"", "_30", "_45", "_60"},
-	increativeinv={st},
+	increativeinv={"st"},
 }
 ap.t_45deg={
 	regstep=2,
@@ -310,7 +310,7 @@ function advtrains.register_tracks(tracktype, def, preset)
 			},
 			mesecons=mesecontbl,
 			luaautomation=luaautomation,
-			drop = increativeinv and def.nodename_prefix.."_"..suffix..rotation or (drop_slope and def.nodename_prefix.."_slopeplacer" or def.nodename_prefix.."_placer"),
+			drop = (drop_slope and def.nodename_prefix.."_slopeplacer" or def.nodename_prefix.."_placer"),
 			}
 	end
 	local function cycle_conns(conns, rotid)