Don't declare variables in headers included in multiple files.

[speachy]

Fixes compiling and linking with gcc10 on Fedora 32.

(Declare them as externs, and properly declare/instantiate them in C files instead. Where it's defined in more than one C file, I commented the others out..)

[speachy]

I should say that if you want me to just delete extra stuff instead of commenting out, I can do that instead. There's also plenty of other variables declared in headers, but they don't trigger compilation/linking problems for one reason or another.

Let me know if what you'd like me to do, if anything, and if I should take this patch any further.

[Interrupt]

It would be cleaner to remove the old locations instead of commenting them out, if you don't mind making that change.

[speachy]

Done!

[Interrupt]

Thanks!