[Bug c++/109021] accept size parameter in extern C

[muecker at gwdg dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109021

--- Comment #2 from Martin Uecker <muecker at gwdg dot de> ---
True. But we could still take it as a hint about where this is not useful to
users to diagnose this as an error.