[llvm] [InferAttrs] Mark errnomem-setting libcalls as such (PR #124742)

[Nikita Popov via llvm-commits]

https://github.com/nikic requested changes to this pull request.

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

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