Add a default clock mod

This mod renders a clock in the top-right corner
and is always available (disabled by default).

It is useful to have a mod available by default
as we work on mod support.

CMake/Assets.cmake

@@ -149,6 +149,7 @@ set(devilutionx_assets
   lua_internal/get_lua_function_signature.lua
   lua/devilutionx/events.lua
   lua/inspect.lua
+  lua/mods/clock/init.lua
   lua/repl_prelude.lua
   nlevels/cutl5w.clx
   nlevels/cutl6w.clx

Source/options.cpp

@@ -1829,7 +1829,15 @@ std::vector<ModOptions::ModEntry> &ModOptions::GetModEntries()
 	if (modEntries)
 		return *modEntries;
 
-	std::vector<std::string> modNames = ini->getKeys(name);
+	std::vector<std::string> modNames = ini->getKeys(key);
+
+	// Add mods available by default:
+	for (const std::string_view modName : { "clock" }) {
+		if (c_find(modNames, modName) != modNames.end()) continue;
+		ini->set(key, modName, false);
+		modNames.emplace_back(modName);
+	}
+
 	std::vector<ModOptions::ModEntry> &newModEntries = modEntries.emplace();
 	for (auto &modName : modNames) {
 		newModEntries.emplace_back(modName);

assets/lua/mods/clock/init.lua

@@ -0,0 +1,6 @@
+local events = require("devilutionx.events")
+local render = require("devilutionx.render")
+
+events.GameDrawComplete.add(function()
+  render.string(os.date('%H:%M:%S', os.time()), render.screen_width() - 69, 6)
+end)