Changed placeholder definitions to work on GCC3.X.
Changed placeholder definitions to work on GCC3.X.

Boost.Bind uses function placeholders on GCC < 4.

Oberon00/luabind,luabind/luabind,Oberon00/luabind,luabind/luabind,rpavlik/luabind,davidar/luabind,alex85k/luabind,rpavlik/luabind,decimad/luabind-deboostified,MrApplejuice/luabind,rpavlik/luabind,alex85k/luabind,mdave88/luabind,ltjax/luabind-deboostified,plsytj/luabind,Wohlhabend-Networks/luabind-deboostified,luabind/luabind,alex85k/luabind,rpavlik/luabind,rpavlik/luabind,mapbox/luabind,luabind/luabind,galek/luabind-deboostified,grafi-tt/luabind,alex85k/luabind,lonski/luabind,Kazade/luabind-deboostified