$ git clone http://ion.nu/git/mcl_compat
commit 0bd2e94a94d5c4e4a77c86159d78bad8b26f6fe2
Author: Alicia <...>
Date:   Sat Mar 3 05:41:27 2018 +0100

    Use diamond pickaxes in place of mese pickaxes.

diff --git a/default/init.lua b/default/init.lua
index 3eb7bcf..e604957 100644
--- a/default/init.lua
+++ b/default/init.lua
@@ -39,6 +39,7 @@ minetest.register_alias("mesecons_materials:silicon", "mcl_core:flint")
 minetest.register_alias("default:mese_crystal", "mesecons_torch:redstoneblock")
 minetest.register_alias("default:mese", "mesecons_torch:redstoneblock")
 minetest.register_alias("default:mese_crystal_fragment", "mesecons:redstone")
+minetest.register_alias("default:pick_mese", "mcl_tools:pick_diamond")
 minetest.register_alias("default:stone", "mcl_core:stone")
 minetest.register_alias("default:wood", "mcl_core:wood")
 minetest.register_alias("default:steel_ingot", "mcl_core:iron_ingot")