No one, except for me, can recompile the AmigaOS 4.x newlib.libray, except for the very few people still supporting a company which changed their business plan into selling a pirated software distributions maybe (AmigaOS 4.1 FE and beyond, AmigaOS 3.1.x/3.2.x, a lot of that is based on stolen AmigaOS 4.x source codes, etc.).
Even if Hyperion broke all of our contracts and I could simply ignore them as well as they do, even for newlib, the only AmigaOS 4.x software I was ever paid for, in contrast to them I still stick to the contracts I signed.
But as long as there is no conflict with the newlib and AmigaOS 4.x NDAs I signed I'd help anyone creating a new AmigaOS 4.x port of newlib, no matter if it's an open source (BSD-like licences only, I'll never support any virulent licences like GPL/LGPL), or a closed source version.

Edit: 99% of the AmigaOS 4.x dependent parts of my newlib.library are based on the clib2 OS and CPU dependent source parts, I only fixed broken and extremely slow functions, but IIRC that were only about 5 functions.

I do believe, it is within the realm of the theoretically possible getting it to work, but it is not very much fun doing the work, and I might decline doing anything further with it, unless there is some really serious motivation involved.