[Bug c/90677] gcc-9.1.0 fails to build __gcc_diag__ souce: error: 'cgraph_node' is not defined as a type

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90677

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
If the GCC 4.6.4 code is not valid C then it's not a bug to reject it.