colorsel: Remove WINDOWING ifdef
colorsel: Remove WINDOWING ifdef

That one was leftover from the times when GDK didn't allow pointer
warping and we had an X11-specific solution.

davidgumberg/gtk,davidt/gtk,jigpu/gtk,Distrotech/gtk2,jessevdk/gtk,Distrotech/gtk2,davidgumberg/gtk,ebassi/gtk,alexlarsson/gtk,davidt/gtk,msteinert/gtk,grubersjoe/adwaita,simokivimaki/gtk,bratsche/gtk-,ahodesuka/gtk,davidt/gtk,ahodesuka/gtk,davidgumberg/gtk,grubersjoe/adwaita,jadahl/gtk,ahodesuka/gtk,Adamovskiy/gtk,Sidnioulz/SandboxGtk,bratsche/gtk-,simokivimaki/gtk,grubersjoe/adwaita,Distrotech/gtk2,bratsche/gtk-,chergert/gtk,jadahl/gtk,jadahl/gtk,alexlarsson/gtk,ebassi/gtk,alexlarsson/gtk,ahodesuka/gtk,ebassi/gtk,davidgumberg/gtk,ahodesuka/gtk,Distrotech/gtk2,grubersjoe/adwaita,Lyude/gtk-,jessevdk/gtk,msteinert/gtk,Lyude/gtk-,Lyude/gtk-,Lyude/gtk-,jessevdk/gtk,Adamovskiy/gtk,jadahl/gtk,alexlarsson/gtk,jessevdk/gtk,davidgumberg/gtk,Adamovskiy/gtk,jigpu/gtk,davidgumberg/gtk,Adamovskiy/gtk,ahodesuka/gtk,grubersjoe/adwaita,jadahl/gtk,Adamovskiy/gtk,alexlarsson/gtk,chergert/gtk,ahodesuka/gtk,grubersjoe/adwaita,ebassi/gtk,jigpu/gtk,chergert/gtk,Lyude/gtk-,msteinert/gtk,ahodesuka/gtk,jigpu/gtk,Adamovskiy/gtk,chergert/gtk,jadahl/gtk,msteinert/gtk,Adamovskiy/gtk,chergert/gtk,msteinert/gtk,jadahl/gtk,jigpu/gtk,Lyude/gtk-,simokivimaki/gtk,bratsche/gtk-,davidt/gtk,grubersjoe/adwaita,bratsche/gtk-,simokivimaki/gtk,Sidnioulz/SandboxGtk,davidt/gtk,Sidnioulz/SandboxGtk,Distrotech/gtk2,jigpu/gtk,Sidnioulz/SandboxGtk,jigpu/gtk,alexlarsson/gtk,jessevdk/gtk,Sidnioulz/SandboxGtk,ebassi/gtk,Adamovskiy/gtk,simokivimaki/gtk,ebassi/gtk,bratsche/gtk-,Sidnioulz/SandboxGtk,chergert/gtk,Lyude/gtk-,Lyude/gtk-,jadahl/gtk,grubersjoe/adwaita,davidt/gtk,jigpu/gtk,jessevdk/gtk,Distrotech/gtk2,simokivimaki/gtk,alexlarsson/gtk,chergert/gtk,davidgumberg/gtk,msteinert/gtk,alexlarsson/gtk,davidgumberg/gtk,chergert/gtk,jessevdk/gtk