[llvm] [X86][CodeGen] Restrict F128 lowering to GNU environment (PR #81664)

[Pranav Kant via llvm-commits]

pranavk wrote:

Yes, that is what I expect Android is doing right now which is breaking it. But I don't know where and if it can be easily fixed in Android. This PR is an effort to avoid reverting the original PR to unbreak Android build for now.

https://github.com/llvm/llvm-project/pull/81664