[clang] Objective C: use C++ exceptions on MinGW+GNUstep (PR #77255)

[Frederik Carlier via cfe-commits]

qmfrederik wrote:

Looks like there was an intermittent issue with GitHub, which should be resolved now.  I've squashed and pushed.  Fingers crossed!

https://github.com/llvm/llvm-project/pull/77255