Zig already supports SystemZ architecture (Tier 3), but only for Linux operating system. It would be awesome to make it work on the z/OS itself as well. z/OS is a 64-bit operating system for IBM mainframes, produced by IBM. It derives from and is the successor to OS/390, which in turn followed a string of MVS versions. Like OS/390, z/OS combines a number of formerly separate, related products, some of which are still optional. z/OS offers the attributes of modern operating systems but also retains much of the functionality originating in the 1960s and each subsequent decade that is still found in daily use (backward compatibility is one of z/OS's central design philosophies).
I believe that such an effort is really just waiting for someone familiar with the OS to put in the work. Have you tried to use the existing tier-3 support to build anything?
Zig already supports SystemZ architecture (Tier 3), but only for Linux operating system. It would be awesome to make it work on the z/OS itself as well. z/OS is a 64-bit operating system for IBM mainframes, produced by IBM. It derives from and is the successor to OS/390, which in turn followed a string of MVS versions. Like OS/390, z/OS combines a number of formerly separate, related products, some of which are still optional. z/OS offers the attributes of modern operating systems but also retains much of the functionality originating in the 1960s and each subsequent decade that is still found in daily use (backward compatibility is one of z/OS's central design philosophies).
IBM recently released their own C/C++ compiler suite, and new version is based on the Clang/LLVM it seems. So the port in fact might be easier than before. Moreover, you can send them a suggestion to sponsor this work through BountySource platform.
https://www.ibm.com/it-infrastructure/z/zos