Fix #9386: compilers failing to compile with LTO by using variants instead of new + unique_ptr

With std::variant all memory can be figured out at compile time, so the compiler needs to keep track of fewer elements. It also saves out a unique_ptr and its memory management, over a slight impact for resolving a setting.

src/table/settings.h.preamble

@@ -54,7 +54,7 @@ static size_t ConvertLandscape(const char *value);
  * on the appropriate macro.
  */
 
-#define NSD(type, ...) std::unique_ptr<const SettingDesc>(new type##SettingDesc(__VA_ARGS__))
+#define NSD(type, ...) SettingVariant { std::in_place_type<type##SettingDesc>, __VA_ARGS__ }
 
 /* Macros for various objects to go in the configuration file.
  * This section is for global variables */

src/table/settings/company_settings.ini

@@ -12,7 +12,7 @@ static void UpdateAllServiceInterval(int32 new_value);
 static bool CanUpdateServiceInterval(VehicleType type, int32 &new_value);
 static void UpdateServiceInterval(VehicleType type, int32 new_value);
 
-static const SettingTable _company_settings{
+static const SettingVariant _company_settings[] = {
 [post-amble]
 };
 [templates]

src/table/settings/currency_settings.ini

@@ -7,7 +7,7 @@
 ; Settings for the in-game custom currency.
 
 [pre-amble]
-static const SettingTable _currency_settings{
+static const SettingVariant _currency_settings[] = {
 [post-amble]
 };
 [templates]

src/table/settings/gameopt_settings.ini

@@ -33,7 +33,7 @@ static std::initializer_list<const char*> _osk_activation{"disabled", "double",
 static std::initializer_list<const char*> _settings_profiles{"easy", "medium", "hard"};
 static std::initializer_list<const char*> _news_display{ "off", "summarized", "full"};
 
-static const SettingTable _gameopt_settings{
+static const SettingVariant _gameopt_settings[] = {
 /* In version 4 a new difficulty setting has been added to the difficulty settings,
  * town attitude towards demolishing. Needs special handling because some dimwit thought
  * it funny to have the GameDifficulty struct be an array while it is a struct of

src/table/settings/misc_settings.ini

@@ -20,7 +20,7 @@ extern bool _allow_hidpi_window;
 #define WITHOUT_COCOA
 #endif
 
-static const SettingTable _misc_settings{
+static const SettingVariant _misc_settings[] = {
 [post-amble]
 };
 [templates]

src/table/settings/settings.ini

@@ -49,7 +49,7 @@ static void UpdateClientConfigValues();
  * assigns its own value. If the setting was company-based, that would mean that
  * vehicles could decide on different moments that they are heading back to a
  * service depot, causing desyncs on a massive scale. */
-const SettingTable _settings{
+static const SettingVariant _settings[] = {
 [post-amble]
 };
 [templates]

src/table/settings/win32_settings.ini

@@ -12,7 +12,7 @@
 #if defined(_WIN32) && !defined(DEDICATED)
 extern bool _window_maximize;
 
-static const SettingTable _win32_settings{
+static const SettingVariant _win32_settings[] = {
 [post-amble]
 };
 #endif /* _WIN32 */

src/table/settings/window_settings.ini

@@ -9,7 +9,7 @@
 
 [pre-amble]
 
-static const SettingTable _window_settings{
+static const SettingVariant _window_settings[] = {
 [post-amble]
 };
 [templates]