r.sim: cleanup of global variables

[petrasovaa]

This is an effort to get clean up the r.sim code:

• group global variables into structures
• remove unused code
• limit scope of some variables
• fix small bug in parallelization code (nwalka variable)

There will be more changes/fixes, but perhaps it would be good to get this merged first.

[nilason]

I love these cleanups, so much readable and manageable code, thanks!
I only left some minor suggestions.

scan-build reported a number of issues. Although they are probably not introduced by this PR, I attached the report (html bundle) here for easy check:

scan-build-2025-02-05-105358-93516-1.zip

[petrasovaa]

I love these cleanups, so much readable and manageable code, thanks! I only left some minor suggestions.

scan-build reported a number of issues. Although they are probably not introduced by this PR, I attached the report (html bundle) here for easy check:

scan-build-2025-02-05-105358-93516-1.zip

Thanks! I will look at it, maybe address some of these in a later PR.

[cwhite911]

@petrasovaa are you planning on removing waterglobs.h? If not, add a comment in the file explaining it's purpose and add nice comment's to the obscure variables names.

[petrasovaa]

@petrasovaa are you planning on removing waterglobs.h? If not, add a comment in the file explaining it's purpose and add nice comment's to the obscure variables names.

Eventually yes.

[echoix]

There was new (or newly triggered, but may be existing) coverity defects in r.sim

[petrasovaa]

There was new (or newly triggered, but may be existing) coverity defects in r.sim

I saw it, I will look at it.