stage1: Work around a small problem in LLVM API
stage1: Work around a small problem in LLVM API

The missing initializer for a single field in the TargetOptions class
was enough to turn the stack protectors into hot garbage.

Fixes #8408

zig-lang/zig,andrewrk/zig,zig-lang/zig,andrewrk/zig,zig-lang/zig