Add generic vxworks GAS target.

[Nick Clifton]

Hi Paul,

> 2005-01-04  Paul Brook  <paul@codesourcery.com>
> 
>  * configure.tgt: Set em=vxworks for *-*-vxworks.
>  * config/te-vxworks.h: New File.

Approved - please apply.

Cheers
   Nick