fix(extern): 初始化并同步 LlvmGen._export_extern_funcs

translator 可能尚无该属性；getattr 初始化后 clear+update，并把同一 dict 引用同步到 LlvmGen，确保 _mangle_func_name 看到跨模块 extern。

lib/Projectrans/Phase2Translator.py

@@ -2405,8 +2405,15 @@ class Phase2Translator:
                             _combined_extern[_node.name] = _sha1_key
                 except Exception:
                     continue
-            trans.translator._export_extern_funcs.clear()
-            trans.translator._export_extern_funcs.update(_combined_extern)
+            _extern_dict = getattr(trans.translator, '_export_extern_funcs', None)
+            if _extern_dict is None:
+                _extern_dict = {}
+                trans.translator._export_extern_funcs = _extern_dict
+            _extern_dict.clear()
+            _extern_dict.update(_combined_extern)
+            _llvm_gen = getattr(trans.translator, 'LlvmGen', None)
+            if _llvm_gen is not None:
+                _llvm_gen._export_extern_funcs = _extern_dict
             if self._shared_generic_class_templates:
                 if not hasattr(trans.translator.ClassHandler, '_generic_class_templates'):
                     trans.translator.ClassHandler._generic_class_templates = {}
@@ -2428,7 +2435,15 @@ class Phase2Translator:
                         raise
                     _vlog().warning(f"收集导出外部函数声明失败: {_e}", "Exception")
             if export_extern_funcs:
-                trans.translator._export_extern_funcs.update(export_extern_funcs)
+                _extern_dict2 = getattr(trans.translator, '_export_extern_funcs', None)
+                if _extern_dict2 is None:
+                    trans.translator._export_extern_funcs = dict(export_extern_funcs)
+                    _extern_dict2 = trans.translator._export_extern_funcs
+                else:
+                    _extern_dict2.update(export_extern_funcs)
+                _llvm_gen2 = getattr(trans.translator, 'LlvmGen', None)
+                if _llvm_gen2 is not None:
+                    _llvm_gen2._export_extern_funcs = _extern_dict2
 
             for includes_dir in self.include_dirs:
                 if os.path.isdir(includes_dir):