mcl_mapgen_core: Make mcl_ocean an optional dependency.

mods/MAPGEN/mcl_mapgen_core/init.lua

@@ -906,6 +906,7 @@ local function register_mgv6_decorations()
 	})
 
 	-- Seagrass and kelp
+	if minetest.get_modpath("mcl_ocean") then
 		local materials = {"dirt","sand"}
 		for i=1, #materials do
 			local mat = materials[i]
@@ -995,7 +996,7 @@ local function register_mgv6_decorations()
 				param2 = 32,
 				param2_max = 160,
 			})
-
+		end
 	end
 
 	-- Wet Sponge

mods/MAPGEN/mcl_mapgen_core/mod.conf

@@ -1,5 +1,5 @@
 name = mcl_mapgen_core
 author = Wuzzy
 description = The core of the MCL2 mapgen
-depends = mcl_init, mcl_core, biomeinfo, mcl_worlds, mcl_ocean, mcl_stairs, mcl_monster_eggs, mcl_structures
-optional_depends = mclx_core, mcl_cocoas, mcl_sponges
+depends = mcl_init, mcl_core, biomeinfo, mcl_worlds, mcl_stairs, mcl_monster_eggs, mcl_structures
+optional_depends = mclx_core, mcl_cocoas, mcl_sponges, mcl_ocean