[clang] [C] Disable use of NRVO (PR #101038)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> We shouldn't merge this PR unless we need an immediate fix, which seems unlikely given how longstanding this behavior is.

Agreed, it's definitely not in shape for committing. As for needing an immediate fix, what surprised me was that two different people ran into this same issue within a few days of each other (https://github.com/llvm/llvm-project/issues/100902 and https://github.com/llvm/llvm-project/issues/100868)

https://github.com/llvm/llvm-project/pull/101038