[llvm] [InferAttrs] Mark floating-point libcalls as errno-writing (PR #124742)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

> To start with, please only add errnomem to the FP libcalls, and nothing else.

Agree, let's begin  with a reduced set of functions first off. Updated, thanks!

https://github.com/llvm/llvm-project/pull/124742