fpspreadsheet: error margin seems to be needed on Windows (FPC 2.6.4+FPC trunk), not on *nix (FPC 2.6.4) in contrast to previous commit.



git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3340 8e941d3f-bd1b-0410-a28a-d453659cc2b4