Deprecate ecbuild_find_{mpi,omp} macros

[wdeconinck]

To be verified, but I am pretty sure that there is no more use case for

• ecbuild_find_mpi
• ecbuild_find_omp

The standard CMake find_package are now sufficiently capable on their own.

I suggest to in first instance print deprecation warnings for these functions in upcoming version, and remove in due course. This is to give current ecbuild projects, if any still, to adapt.

It should be documented clearly that these functions are deprecated and should not be used in new projects.

[eap]

We use these at JCSDA. Our use of these macros are probably in place now for historical reasons. I will replace our use of these macros and run a build and report back here.

[eap]

No objection from us: I've tested this with our main packages and all works as intended. I'll be submitting this in the jedi codebase for all maintained code.

[marcosbento]

@wdeconinck, you mention deprecating ecbuild_find_(mpi|omp), but what about companion ecbuild_enable_(mpi|omp), ecbuild_include_mpi, and ecbuild_enable_ompstubs macros? Shouldn't those also be deprecated?

If you agree, it seems that all macros in ecbuild_find_mpi.cmake and ecbuild_find_omp.cmake should be marked as deprecated and eventually removed.

I can put together the changes so you can review them -- we should be able to include this in the upcoming synchronised release.

[wdeconinck]

Yes in fact that was what I intended. Sorry if that was not clear. @eap does that follow what you thought as well?
Everything within the ecbuild_find_{mpi,omp}.cmake files should be deprecated and the files should eventually be removed.

[marcosbento]

Merged to develop.