Use oneapi compiler

[anton-seaice]

For ongoing support and better optimisation on new hardware, we need to move to using the Intel Oneapi / LLVM compilers instead of the current Intel Classic compilers. Initial discussion is here

We expect this change to not be bit for bit.

To-do:

• Add latest compiler to spack-config - Add latest version of the Intel OneAPI compilers on gadi spack-config#52
• Figure out and raise an issue on why spack doesn't find oneapi compilers correctly ( e.g. https://github.com/ACCESS-NRI/ACCESS-OM3/actions/runs/12799074164/job/35684422602)
• Confirm if oneapi matches against when=%intel in spack ? e.g. https://github.com/ACCESS-NRI/spack-packages/blob/288ef380159af4536137b40360b2a87c043b7ce1/packages/access-om3-nuopc/package.py#L58 and
  https://github.com/ACCESS-NRI/spack-packages/blob/288ef380159af4536137b40360b2a87c043b7ce1/packages/access-om3-nuopc/package.py#L65
• Confirm if oneapi matches against (CMAKE_Fortran_COMPILER_ID MATCHES "Intel")
• (Optional ?) - check compiler flags used in CMakeLists ?

It doesn't really matter if we do this before or after #34 / #35 which uses the new build system (we just need to make sure CMake and spack changes, if required are done in all the related repositories / packages.

I suggest we do this seperately from code changes (e.g. 2025.01.0 could be build with intel-classic and 2025.01.1 could be oneapi with the same source code). This makes it easier to examine any differences in the results.

I may have added extra steps here - let me know if you have done some of these already @micaeljtoliveira

[micaeljtoliveira]

Confirm if oneapi matches against when=%intel in spack ?

No, it doesn't.

[micaeljtoliveira]

Confirm if oneapi matches against (CMAKE_Fortran_COMPILER_ID MATCHES "Intel")

Yes, this matches correctly.

[chrisb13]

Just seen this new issue, great to see some of the things we discussed here, already being addressed!