Change Xserver screen through libXrandr. For complex configurations,
all outputs must have corresponding size modes. As a special case, if
the client requests a single screen with an odd size (for example when
adjusting the size of a non-fullscreen vncviewer), find a smaller
suitable mode, and reduce the framebuffer size as well.

XFixes only reports cursor changes. We must manually call
XFixesGetCursorImage() when starting.

Define ledNames in XDesktop.cxx, rename N_LEDS to XDESKTOP_N_LEDS