Make TranslationServer singleton variable inline.

This change avoids the problem known as 'Static Initialization Order Fiasco' (SIOF).

See the following PR for more explanation: godotengine#94683

Co-authored-by: Gabor Koncz <gabor.koncz@migeran.com>

Author: 2 people

core/string/translation_server.cpp

@@ -388,8 +388,6 @@ StringName TranslationServer::translate_plural(const StringName &p_message, cons
 	return main_domain->translate_plural(p_message, p_message_plural, p_n, p_context);
 }
 
-TranslationServer *TranslationServer::singleton = nullptr;
-
 bool TranslationServer::_load_translations(const String &p_from) {
 	if (ProjectSettings::get_singleton()->has_setting(p_from)) {
 		const Vector<String> &translation_names = GLOBAL_GET(p_from);

core/string/translation_server.h

@@ -48,7 +48,7 @@ class TranslationServer : public Object {
 
 	bool enabled = true;
 
-	static TranslationServer *singleton;
+	static inline TranslationServer *singleton = nullptr;
 	bool _load_translations(const String &p_from);
 	String _standardize_locale(const String &p_locale, bool p_add_defaults) const;