[clang] fix bug that undefined internal is a warning only for -pedantic-errors (PR #98016)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> > Yup, that resolved the issue: https://lab.llvm.org/buildbot/#/builders/144/builds/2082 -- not certain why that builder has a different default value for `-std` though. Clang defaults to C17, but that builder seems to be defaulting to C99.
> 
> This bot targets the PS4 which has kept an older version of the standard as the default for compatibility reasons.

Ahhhhh! I remembered that the PS used older versions of the standard, but I didn't realize that was *this* bot. "SIE" -- Sony Interactive Entertainment... now I get it. Thank you! :-)

https://github.com/llvm/llvm-project/pull/98016