Gentoo raises s390x baseline to z10 - 14/04/2025 00:00 GMT

Since more and more software for s390x assumes the presence of a more recent
processor, we will raise the ISA baseline in 64bit s390x profiles for the
catalyst stage builds and the published binary packages from z900 to z10 (i.e.,
-march=z10).

* If you are running an installation and emerge locally from source, this does
  not affect you.

* If you are running an installation and use our binary packages, please make
  sure you have compatibility for z10 or switch to building from source.

* The 64bit s390x stages will only work with machines compatible with z10.

* This does not affect the 31bit s390 stages or packages.

The z10 Enterprise Class (2097 series) was introduced in February 2008 [1],
which essentially means everyone except hardware archaeologists should be fine.

Note that z10 is still a very conservative setting; on modern machines a newer
ISA is strongly recommended.

[1] https://en.wikipedia.org/wiki/IBM_Z