Add -Wshadow=local to warnings and fix reported issues (#25316).

[marxin]

I've made a mechanical changes in order to silent the warning.
I'm also attaching a script that I used to compare that objdump -S is identical (objdump-S.diff).
Moreover, I checked that .roda and .data are equal mudulo git revision and new assert strings (objdump-data-rodata.diff), it's quite nicely seen in output of strings command (strings.diff).
Please tell me what you think about the changes?

difference.tar.gz

[starry-abyss]

I think it makes more sense for names to contain some information about the variable meaning, not just add "2" suffix.

[marxin]

I think it makes more sense for names to contain some information about the variable meaning, not just add "2" suffix.

Sure, that makes perfectly sense, but my project knowledge is very low. The "2" suffix was the easiest way how to deal with it. Note that even using loop names as i, j, k can be theoretically improved to a more descriptive name.

[akien-mga]

I can have a look at each occurrence to find better names if you want, and amend the commit accordingly.

[marxin]

I can have a look at each occurrence to find better names if you want, and amend the commit accordingly.

Great, I would appreciate that.

[akien-mga]

I can have a look at each occurrence to find better names if you want, and amend the commit accordingly.

I reviewed a few of occurrences, but eventually had to give up in front of the sheer amount.
I reviewed all of core at least, and replaced the E2 occurrences by F where appropriate, as it's what we do usually.
I also had to fix -Werror=shadow-local in the mono module (cc @neikeq).

[neikeq]

Why are all the previous tclass locals being renamed?

[akien-mga]

Sorry, GH didn't show me your comment before I clicked "merge" somehow.

In this method, all the tclass in this local scope were shadowing the definition at line 580:

GDMonoClass *tclass = GDMono::get_singleton()->get_class(mono_object_get_class(p_obj));

The renamings in the other methods are actually a mistake, I acted based on a list of -Werror=shadow-local errors and didn't properly check the line numbers.

[akien-mga]

Thanks @marxin for the impressive work!