C++20 DR 2237 disallows simple-template-id in cdtors, so you
can't write
template<typename T>
struct S {
S<T>(); // should be S();
};
This hasn't been a problem until now but I'm adding a warning about it
to -Wc++20-compat which libitm apparently uses.
libitm/ChangeLog:
* containers.h (vector): Remove the template-id in constructors.
8ca585e56c