Test failure on Fedora 34 because of gdb script failure

[nyh]

On Fedora 34, with gcc 11.2.1,make check fails on tracing_smoke_test:

Traceback (most recent call last):
  File "/home/nyh/osv.tmp2/osv/scripts/loader.py", line 1004, in unique_ptr_get
    return u['_M_t']['_M_t']['_M_head_impl']
gdb.error: Request for member '_M_head_impl' is ambiguous in type 'std::tuple<char*, void (*)(void*)>'. Candidates are:
  '<unnamed type> std::_Head_base<1, void (*)(void*), false>::_M_head_impl' (std::tuple<char*, void (*)(void*)> -> std::_Tuple_impl<0, char*, void (*)(void*)> -> std::_Tuple_impl<1, void (*)(void*)> -> std::_Head_base<1, void (*)(void*), false>)
  '<unnamed type> std::_Head_base<0, char*, false>::_M_head_impl' (std::tuple<char*, void (*)(void*)> -> std::_Tuple_impl<0, char*, void (*)(void*)> -> std::_Head_base<0, char*, false>)

I don't know how we never saw this failure on Jenkins (I was under the impression it had Fedora 34 too, but maybe it doesn't?).