[vtkusers] build variables recalled in tcl

[anast.jm at pg.com]

Is there a way in tcl to access the variables that I'm assuming get defined
during the vtk build such as VTK_LARGE_FLOAT. I've also been interested in the
variables that define the vtkDataTypes like char=2, uchar=3...double=11. I've
been hard codng these in my tcl scripts but this seems silly. Is there a list of
all these types of variables and a tcl utility that loads em?? Any tips
appreciated....john