[Bug c++/120498] error: either all initializer clauses should be designated or none of them should be when designated-initialising nested union members(?) (same code accepted as C)

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120498

--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The correct way to do it is to provide an initializer for sa.u, and that
initializer can initialize .sa_handler i.e.

  struct sa sa = {.sa_flags = 0, .u = {.sa_handler = 0} };