[compiler-rt] [compiler-rt] [code-quality] replaced insecure function calls in _initializeAvailabilityCheck (PR #98659)

[Saleem Abdulrasool via llvm-commits]

compnerd wrote:

I don't think that this adds much value, but more importantly I'm concerned about any potential ABI impact of this type of change. I think that this would need sign off from someone at apple. @Bigcheese or @vsapsai mind helping identify the right person to help with the implications for backdeployment?

https://github.com/llvm/llvm-project/pull/98659