Update on the gcc matter:
1. The issue is related to a specific case of TLS implementation and is not exclusive to powerpc but apparently affects macOS < 10.11.
2. There is no fix for it right now, but it is expected, so for the moment I am not gonna revert the changes. (There is no reason to go back to gcc14: in the worst case a build of gcc16 with `--disable-tls` will work fine, which is what gcc14 was doing anyway.)
3. If you build gcc16 now, you will need to rebuild it again soon. So unless on a fast hardware, perhaps refrain from updating until the issue is fixed.
4. Once gcc/libgcc are updated, some ports will be broken. Extent is unknown but looks like only C++ ports that use TLS are affected. I have pushed temporary fixes to a few which I discovered, so that the set-up is working.