[clang] [Clang][OpenCL] Fix Missing `-fdeclare-opencl-builtins` When Using `--save-temps` (PR #131017)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> Yeah these are implemented in bitcode file, therefore it needs the front end to be able to recognize it instead of treating it as an unknown symbol.

In a normal world they would just be in a header and then the library would get linked in later.

https://github.com/llvm/llvm-project/pull/131017