[clang] Add clang warning if fp exception functions are called without appropriate flags/pragmas (#128239) (PR #187860)

[Marcos Ramirez Joos via cfe-commits]

maarcosrmz wrote:

@efriedma-quic
Since you reported this issue and gave some guidance on how to fix it in [this comment](https://github.com/llvm/llvm-project/issues/128239#issuecomment-3676550018), I would appreciate if you could take a look at my changes. Thank you in advance.

https://github.com/llvm/llvm-project/pull/187860