[fpc-pascal] Variable export always uppercase?

[Max Vlasov]

Hi,
I'm trying to trick some c-libraries that use errno variable to think
that it's located in my sources (Windows, MingGw compiled libraries).
if I declare

var
  ___errno: integer;
...
exports
  ___errno;
end.

I still get error
testproj.lpr(27,1) Error: Undefined symbol: ___errno

if I look inside the unit's .o file, I find this symbol uppercase ( ___ERRNO).

I also saw that several issues existed and fixed in the matis about
uppercase exports, but they were about functions. Can variables still
be exported in uppercase? Or did I go a wrong way and it's not
possible to do such trick?

Thanks

Max