[clang] [Clang] Allow raw string literals in C as an extension (PR #88265)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> In that case I think it might just make sense to ignore the flag in C++11 and later then and allow it before C++11.

I think that makes the most sense.

https://github.com/llvm/llvm-project/pull/88265