Method to detect 4.6 or 4.7.

[Chris Johns]

Hello,

I need to detect if code is being built for 4.6 or 4.7. For example the 
new "rtems/bsdnet/servers.h" file is needed for 4.7 but not 4.6.

What is the preferred method of detecting the difference ?

An autoconf test would be fine.

Regards

-- 
  Chris Johns