adapt mod to 5.0.0 changes

depends.txt

@@ -1,2 +0,0 @@
-default
-moreores?

mod.conf

@@ -1 +1,4 @@
 name = uniham
+depends = default
+optional_depends = moreores
+descripton = The mod adds various hammers that can be used to crush nodes and an API to register own hammers. See <https://gitlab.com/4w/uniham> for details and documentation

system/registry.lua

@@ -1,9 +1,8 @@
 -- Localize & Initialize
 local register_hammer = uniham.register_hammer
 local modpath = uniham.modpath
-local registry = modpath..DIR_DELIM..'registry'
-local depends = io.open(modpath..DIR_DELIM..'depends.txt', 'rb')
 local log_prefix = '['..minetest.get_current_modname()..'] '
+local registry = modpath..DIR_DELIM..'registry'
 
 
 -- Check if a file exists
@@ -23,22 +22,15 @@ local file_exists = function (file_name)
 end
 
 
--- Check if the depends.txt file was read properly
---   Iterate over all lines
---     Check if the mod exists
---       Check if a registry file exists
---         dofile() the file and print a log message
-if depends ~= nil then
-    local lines = {}
-    for line in depends:lines() do
-        local modname = line:gsub('?', '')
-        if minetest.get_modpath(modname) then
-            local registry_file = registry..DIR_DELIM..modname..'.lua'
-            if file_exists(registry_file) then
-                dofile(registry_file)
-                local message = 'Loaded built-in '..modname..' support'
-                minetest.log('action', log_prefix..message)
-            end
-        end
+-- Load built-in support for supported mods
+local config = Settings(modpath..DIR_DELIM..'mod.conf')
+local depends = config:get('depends')..', '..config:get('optional_depends')
+
+for modname in depends:gmatch('[0-9a-z_-]+') do
+    local registry_file = registry..DIR_DELIM..modname..'.lua'
+    if file_exists(registry_file) then
+        dofile(registry_file)
+        local message = 'Loaded built-in '..modname..' support'
+        minetest.log('action', log_prefix..message)
     end
 end