[vtkusers] VTK CVS currently kinda messed up.

[kent williams]

I'm using VTK CVS to pull in the latest and greatest vtkContourWidget,
which depends on some other post-last-official-release stuff, so I
can't really separate it out.

This is normally not a problem, but today there's some squirrellyness
showing up in the build on Mac OSX 10.4.11:


1. VTK_USE_TK -- if you're in the 'build tcl/tk for X11 even though
you're on a Mac' world, this symbol is defaulting to off, but
KWWidgets depends on it.  It used to default on -- I think -- at any
rate if you build X11 on OSX you lose unless you explicitly set it to
on.

2. SQL in the IO directory -- on OSX, can't find 'mysql.h' -- and I
don't really care. If you look at the CMakeLists.txt it adds source
files to the IO library that depend on MySQL being found, even if
VTK_USE_MYSQL is set to off.