[Rd] Crash of "approx" on extreme case

[Uwe Ligges]

Fan wrote:
>  > approx(1:2, c(NA,NA),1.5)
> 
> Version: 1.9.0
> OS: Windows XP
> 
> ______________________________________________
> R-devel at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-devel


Already fixed in R-patched to be R-1.9.1 in a few weeks:

     o   approx(list(x=rep(NaN,9),y=1:9), xout=NaN) does not seg.fault
     anymore (PR#6809).

Uwe Ligges