Remove agbcc

[mrgriffin]

Title, in preparation for 1.10.

Fixes #4946

[AlexOn1ine]

is there anything left for the pr to be merged?

[mrgriffin]

I think it works and removes everything it should/doesn't remove everything it shouldn't, but a second set of eyes could be good?

[tertu-m]

How does this handle if MODERN blocks in the existing codebase?

[hedara90]

How does this handle if MODERN blocks in the existing codebase?

MODERN is still set to 1 in the Makefile so they should work the same

[hedara90]

The #if MODERN blocks in the code are also unnecessary now since it's always modern.
I tested compiling with those removed, and all tests pass at least

[mrgriffin]

Good comments:

• #if MODERN these could go. I think a lot of them come from pret? All the #if BUGFIXes do, and those are all essentially forced on under modern. I felt like that could be quite invasive, but you're welcome to PR to my PR if the invasiveness is worth it :)
• build/modern and build/modern-test. I didn't think about these, but I think they probably shouldn't just change to what the agbcc directories are, because I think that would cause people who update to 1.10 to try and link modern-compiled and agbcc-compiled artifacts until they make clean to remove all the agbcc-compiled ones?
• tidymodern yeah, that could be just something else. What would you want to call it? tidy currently does tidymodern and tidycheck. I suppose it could be inlined into tidy? I doubt there's much use for "delete the ROM build artifacts, but not the test build artifacts"?

[hedara90]

I can PR the #if MODERN removal after this is in, keeps the invasiveness down.
Build directories, we can wait with that until 1.11 (or 1.10.x) then, by then all agbcc artifacts should be gone.
And yea, just tidy works I'd say, if someone really needs "delete the ROM build artifacts, but not the test build artifacts", they can scream at me.

[tertu-m]

So to be clear I think the code in those blocks should stay around (most of it seems like things like alignment checks)

[tertu-m]

Okay in that case if MODERN is set to 1 i have no issues with that.

[hedara90]

Further changes to clean up the remnants of the agbcc/modern split can be addressed at a later time.