advice needed: bug44456 addition of ODF-formula datedif to calc

[Winfried Donkers]

> > The function originates from Lotus 1-2-3 where it was called DATEDIF,
> > MS-Excel called it the same, and ODF just adopted that name. The
> > DATEDIFF function you mention is something different (VBA?).
> 
> I don't know if the function needs to be added to xlformula.cxx and/or
> lotform.cxx (see comment in code)
This is still an open question for me.
 
> I do not have Excel, so I can't test if an xls-file with DATEDIF() imports ok.
 
> There is one problem with building: sc/qa/unit/ucalc.cxx produces an error:
I managed to solve this. (I wasn't aware that ucalc.cxx had all functions hardcoded)

Once the xlformula.cxx/lotform.cxx question has been answered, I will submit the patch.
For those who wish to test and comment on it already, I attached the latest diff in the bug-base

Winfried