[libc-commits] [libc] [libc] Replace -nostdlib++ flag when building with gcc and add placement new operator to HermeticTestUtils.cpp. (PR #78906)

[Schrodinger ZHU Yifan via libc-commits]

https://github.com/SchrodingerZhu approved this pull request.

The change itself looks good to me. Just curious that if `COMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC` guarantees the compatibility.

https://github.com/llvm/llvm-project/pull/78906