fix missing includes of <X11/Xfuncproto.h>
Several places using _X_ATTRIBUTE_PRINTF macro from X11/Xfuncproto.h but missing to include it, so it depends on other headers whether it's included by mere accident, which quickly causes trouble if include order changes. Cleaning that up by adding explicit include statements.
Signed-off-by: Enrico Weigelt, metux IT consult info@metux.net