[clang] [clang][driver] Improve warning message for complex range overrides and GCC incompatibility (PR #149028)

[Shunsuke Watanabe via cfe-commits]

s-watanabe314 wrote:

Thank you for agreeing! I'll post a patch to fix only the overriding warnings around next week.

https://github.com/llvm/llvm-project/pull/149028