[vtkusers] problem compiling VTK 5.10.0 rc2 on a Mac

[A A]

When I build VTK 5.10.0 rc2 on a mac running OS X 10.6 with the
default options, it builds fine. But when I set the following:

CMAKE_OSX_DEPLOYMENT_TARGET  = 10.5
CMAKE_OSX_SYSROOT = /Developer/SDKs/MacOSX10.5.sdk

the following compiler error occurs:

[ 97%] Building CXX object
Charts/CMakeFiles/vtkCharts.dir/vtkAbstractContextItem.cxx.o
/Users/test/software/vtk/vtk-5.10.0-rc2/VTK5.10.0.RC2/Charts/vtkAbstractContextItem.cxx:
In member function ‘virtual vtkAbstractContextItem*
vtkAbstractContextItem::GetPickedItem(const vtkContextMouseEvent&)’:
/Users/test/software/vtk/vtk-5.10.0-rc2/VTK5.10.0.RC2/Charts/vtkAbstractContextItem.cxx:166:
error: no match for ‘operator!=’ in ‘it != std::vector<_Tp,
_Alloc>::rend() [with _Tp = vtkAbstractContextItem*, _Alloc =
std::allocator<vtkAbstractContextItem*>]()’
/Users/test/software/vtk/vtk-5.10.0-rc2/VTK5.10.0.RC2/Common/vtkWeakPointerBase.h:97:
note: candidates are: bool operator!=(const vtkWeakPointerBase&, const
vtkWeakPointerBase&)
/Users/test/software/vtk/vtk-5.10.0-rc2/VTK5.10.0.RC2/Common/vtkWeakPointerBase.h:97:
note:                 bool operator!=(vtkObjectBase*, const
vtkWeakPointerBase&)
/Users/test/software/vtk/vtk-5.10.0-rc2/VTK5.10.0.RC2/Common/vtkWeakPointerBase.h:97:
note:                 bool operator!=(const vtkWeakPointerBase&,
vtkObjectBase*)
make[2]: *** [Charts/CMakeFiles/vtkCharts.dir/vtkAbstractContextItem.cxx.o]
Error 1
make[1]: *** [Charts/CMakeFiles/vtkCharts.dir/all] Error 2
make: *** [all] Error 2

Is there a way to build the new version of vtk on macs running 10.6
and still support 10.5?