Moved GPU usage withing the required #ifdefs

[boris-martin]

When disabling CUDA, a few compilations arise. After investigation, it seems a few lines where placed outside of the macros checking whether or not CUDA is used. I fixed heuristically (fixing until it compiled) and haven't tested thoroughly the impacts of the change.

[Kabbone]

These changes shouldn't be enough. There are some arguments which need to be changed. Most necessary changes you can find in my branch cudaless, but this would need some rework to make it flexible during compile time.
Kabbone/PaStiX4CalculiX@pastix_push2...Kabbone:cudaless

[boris-martin]

These changes shouldn't be enough. There are some arguments which need to be changed. Most necessary changes you can find in my branch cudaless, but this would need some rework to make it flexible during compile time. Kabbone/PaStiX4CalculiX@pastix_push2...Kabbone:cudaless

Indeed, I realized afterwards that my changes allowed the code to compile with CUDA disabled but installed, but on machines where it was not installed, it is still not enough. (mostly because of CUBLAS)
Thanks for pointing your branch, this has gone way above my skill level