[fpc-pascal] SetCodePage in older FPC 3.0.4

[Alexey Tor.]

I am making small unit https://github.com/alexey-t/aencoding

so I need to know:

a) will it work on FPC 3.0.4? do I need to use {$ifdef}?

b) my trick to set CP_UTF8 at the end of nnnnFromTo function is ok?

c) what encoding numbers (e.g. 936, 950) exist in FPC 3.3 but didn't 
exist in FPC 3.0.4?

-- 
Regards,
Alexey