[Lazarus] Compilation error on an old source

[Jean SUZINEAU]

It's likely because it was written for an older version of the function 
IsEmptyStr,
the current one takes an array of char as second parameter.

So I think IsEmptyStr(auxstr,'0') should become IsEmptyStr(auxstr,['0'])

https://www.freepascal.org/docs-html/rtl/strutils/isemptystr.html