useless definition of _SV_RULER_CXX ?

[Rodolfo]

While working on a patch, I saw this #define inside a .cxx file... [1]

Some (private) methods of class Ruler are declared inside an #ifdef of
it [2]. But that can be only triggered inside ruler.cxx file [1] : a
trick by defining _SV_RULER_CXX right before including the header
file.

Is it really necessary? Shouldn't SVT_DLLPRIVATE do this
completely-"private"-thing?

Note there's some "using namespace" inside it.

$ git grep _SV_RULER_CXX
svtools/inc/svtools/ruler.hxx:#ifdef _SV_RULER_CXX
svtools/source/control/ruler.cxx:#define _SV_RULER_CXX
svtools/source/control/ruler.cxx:#ifdef _SV_RULER_CXX

[1] http://opengrok.libreoffice.org/xref/core/svtools/source/control/ruler.cxx#27
[2] http://opengrok.libreoffice.org/xref/core/svtools/inc/svtools/ruler.hxx#647