draft: adjusted for Intel oneAPI

[MarDiehl]

works with 2024.2.1. PCH handling and Fortran compiler are not version dependent, probably breaks older systems

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Further comments

Intel oneAPI contains new, LLVM-based compilers which have some incompatibilities to the older compilers. This makes b2 work with these new compilers.

Note: I believe that this change does not work on older systems, but to make it compatible I need help for writing jam files and, ideally, setting up a CI for Intel compiler

@hainest: This seems to be the place for the changes

[grafikrobot]

setting up a CI for Intel compiler

Can you point me to set up instructions for the compiler? Preferably for older versions too. And I can try and add some CI.

[MarDiehl]

setting up a CI for Intel compiler

Can you point me to set up instructions for the compiler? Preferably for older versions too. And I can try and add some CI.

There are Docker images on https://hub.docker.com/r/intel/oneapi. As far as I know, the Fortran compiler is only included in the HPC toolkit.
The images are huge, I remember some cases where GitHub actions failed due to lack of memory.

Regarding older versions: Intel offers downloads of older versions only to paying customers and I can't see older tags on DockerHub. I think there are two ways forward:

1. build custom images and simply keep the old versions. I could imagine that hosting such images publicly violates Intels terms of usage.
2. contact Intel and ask if they have some kind of free support for open source projects that allows to obtain older versions.