Index: gcc/d/d-lang.cc
--- gcc/d/d-lang.cc.orig
+++ gcc/d/d-lang.cc
@@ -1729,6 +1729,12 @@ d_enum_underlying_base_type (const_tree type)
   return TREE_TYPE (type);
 }
 
+const char *
+fname_as_string(int pretty_p __attribute__((__unused__)))
+{
+	return NULL;
+}
+
 /* Definitions for our language-specific hooks.  */
 
 #undef LANG_HOOKS_NAME