Index: uspace/lib/cpp/include/impl/string.hpp
===================================================================
--- uspace/lib/cpp/include/impl/string.hpp	(revision 15b8b85e2e9a1649931bc9554ddfe14d2ab92e46)
+++ uspace/lib/cpp/include/impl/string.hpp	(revision 8d0953ffff2941f57c23c65269562578379a68d7)
@@ -1465,4 +1465,7 @@
             allocator_type allocator_;
 
+            template<class C, class T, class A>
+            friend class basic_stringbuf;
+
             /**
              * Arbitrary value, standard just requires