Just documenting it here for awareness. I spun up a Rocky Linux 9 container last night, and was able to get the out-of-the-box configuration building with the llvm-toolset (clang-18) package. I had to install a handful of dependencies, but they were all available in the standard repositories. Given that Rocky is intended to mirror Red Hat Enterprise Linux (RHEL), that does bode well for tt-metal being able to build on RHEL9.
Edit: The new sub-dependency libisl.so.23 (which was hooked today) is not available in any of the Rocky/Fedora repos, which is stuck on v0.16. So any Rocky builds going forward are going to need to build libisl. See #21635 for more information.
Edit2: A recent update added support for OpenMPI. I haven’t tested this on the rocky container (yet), but on fedora, the openMPI/-devel packages put everything under /usr/lib64/openmpi with subdirectories bin lib include share. This appears to be because redhat ships both openmpi as well as the alternate implementation mpich. The FindOpenMPI.cmake that ships with the cmake-data package doesn’t seem to find it by default (I probably need to put in a ticket with RH), so the workaround was to add /usr/lib64/openmpi/bin etc to their respective PATH environment variables. Just documenting this here since its the same distro provider.