[Bug c/69960] "initializer element is not constant"

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69960

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The C standard says it's not a constant, but clang accepts it as an extension.
That doesn't make it valid C though.