Fix pointer mismatchings and other warnings

[AtariDreams]

Many of these castings are unneeded if we change the variables to work better with each other.

Note that none of the public facing functions had their signature changed.

[bagder]

I review a part of this PR and it made me question what you are doing so I paused.

[bagder]

quite bad

[AtariDreams]

Not anymore

[bagder]

This PR starts to smell like a million tiny changes you think should be done, but most of them are now not about "pointer mismatches and other warnings". It's a busload of various unrelated changes that should not be in the same PR. It makes this PR very hard to review and next to impossible to ultimately merge.

[jay]

You must have very strict compiler settings for the warnings you are seeing. Many of these changes are not needed.

We allow counter variables to go negative or wrap around. For example this is acceptable:

int foo = 5;
while(foo--) {
}
return

We allow subscript values to be a signed integer type. For example this is acceptable:

int foo = 5;
bar[foo]

We allow char * function parameters.

I'm closing this PR in favor of #9835 which is what is left after my review.