Clarification on newlib version for building AMDGCN offloading backend

[Wileam Yonatan Phan via Gcc]

Hi,

I'm working on adding a build recipe for GCC with AMDGCN offloading backend in 
Spack. Can anyone clarify the following sentence listed on the wiki?

>The Newlib version needs to be contemporaeous with GCC, at least until the ABI 
>is finalized.
<https://gcc.gnu.org/wiki/Offloading#How_to_build_an_offloading-enabled_GCC>

What are the correct contemporaneous versions for each version of GCC >= 10?

Thanks,
Wil