[clang] opencl: Ensure printf symbol is not mangled. (PR #150210)

[Felix Weiglhofer via cfe-commits]

fweig wrote:

> Correct me if I'm wrong, but I believe `release/20.x` is now closed and no more 20.x releases are being planned. We can backport it to 21.x if that helps (but that won't help 20.x based environments).

Thanks for the info. I'm not very familiar with LLVM release policies. Backport to 21.x would help too. We'll have to live with patching until we can switch to >=21...

https://github.com/llvm/llvm-project/pull/150210