[clang] [clang][CodeGen] Zero init unspecified fields in initializers in C (#97459) (PR #97121)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

Ping @rjmccall @efriedma-quic -- I'd like to see this get into the release so that the Linux kernel can be built with Clang 19.

https://github.com/llvm/llvm-project/pull/97121