[Rd] y label for X11 graphics

[Therneau, Terry M., Ph.D.]

In the following plot, the y label is missing if it is too long.

x11(type="Xlib")
plot(1:5, 1:5, ylab="Do, a deer, a female deer")   # missing label
plot(1:5, 1:5, ylab="Do")                          # label is present

All is well for x11(type="cairo")

This is true both under R devel 2017-09-01 on xubuntu (my desktop), and 3.4.1 on Centos 
6.9 (department servers).


A minor question is why my locally compiled version defaults to Xlib rather than cairo, 
since both work as explicit arguments to the x11() command.

Terry T.