update to use new signs_lib API -- requires signs_lib commit 4ff54c9a and above

depends.txt

@@ -12,3 +12,4 @@ technic?
 nyancat?
 usesdirt?
 worldedit?
+signs_lib?

init.lua

@@ -362,6 +362,14 @@ if not minetest.get_modpath("usesdirt") then
 		groups = {cracky=3, stone=2},
 		sounds = default.node_sound_stone_defaults()
 	})
+
+	if minetest.get_modpath("signs_lib") then
+		signs_lib.allowed_poles["usesdirt:dirt_brick_fence"]        = true
+		signs_lib.allowed_poles["usesdirt:dirt_fence"]              = true
+		signs_lib.allowed_poles["usesdirt:dirt_cobble_stone_fence"] = true
+		signs_lib.allowed_poles["usesdirt:dirt_stone_fence"]        = true
+		signs_lib.allowed_poles["usesdirt:dirt_stone_fence"]        = true
+	end
 end
 
 -- Stairs/slabs defs, conversion of normal -> mossy items