[Kst] extragear/graphics/kst/src/plugins/shift

[Brisset, Nicolas]

> extragear/graphics/kst/src/plugins/shift/shift.c:11: warning: 
> declaration of `nan' shadows a global declaration
> <built-in>:0: warning: shadowed declaration is here
> 
> This should be cleaned up I think. In any case, defining nan 
> this way is unportable.  Have a look at kstmath.h.
I was wondering: is it OK for plugins to include kstmath.h, or should
they be as independent as possible ?