[lldb] Fix StdUnorderedMapSynthProvider for GCC

Author: DrSergei

lldb/examples/synthetic/gnu_libstdcpp.py

@@ -68,6 +68,11 @@ def extract_type(self):
         template_arg_num = type.GetNumberOfTemplateArguments() - 1
         allocator_type = type.GetTemplateArgumentType(template_arg_num)
         data_type = allocator_type.GetTemplateArgumentType(0)
+        if data_type.IsValid():
+            return data_type
+        type = self.head.GetType()
+        head_type = type.GetTypedefedType().GetTypedefedType()
+        data_type = head_type.GetTemplateArgumentType(1)
         return data_type
 
     def update(self):