Cannot override amdgpu-function-calls in downstream codes

[psharda]

When amrex is compiled as a submodule in quokka, and quokka is compiled for AMD GPUs, this line sets amdgpu-function-calls=false which does not seem to be overridden even if we set it to true in quokka CMakeLists:

https://github.com/psharda/amrex/blob/a5720c951e81e78097b9b00aeb1aac2c3b4366a6/Tools/CMake/AMReXParallelBackends.cmake#L271

How can a downstream code like quokka change the value of amdgpu-function-calls without having to go into amrex CMake files and manually setting it to true? This is needed to compile problems in quokka that use chemistry (microphysics).

This is related to quokka-astro/quokka#569

[ax3l]

Ideas:

• We could make this flag PRIVATE instead of PUBLIC to keep it contained inside AMReX.
• We can add an option to enable/disable this work-around. Is it even still needed?

[BenWibking]

Ideas:

• We could make this flag PRIVATE instead of PUBLIC to keep it contained inside AMReX.
• We can add an option to enable/disable this work-around. Is it even still needed?

I think making it PRIVATE would solve our issue.

When compiling our reaction network, we still need this.