[libcxx] [llvm] [libc++] Add support for picolibc and newlib in RUNTIMES_USE_LIBC (PR #147956)

[Volodymyr Turanskyy via llvm-commits]

voltur01 wrote:

Hi, how can we progress this to a conclusion: accept or reject? I think the only outstanding question above was if we needed to provide compatibility with the old way and a warning.

Here is the patch for possible warning that I can incorporate back, if there is agreement: https://github.com/llvm/llvm-project/pull/147956/commits/a8769880f65faf2abce6bee04b480efd5c0bf571

Thanks!

https://github.com/llvm/llvm-project/pull/147956