(Cross posted from the build forum to make sure I've caught everyone).

We're changing the build a bit in order to allow drivers to be built without having to check out the entire networking 
source tree.  As a first step, an intermediary build directory (sys/buildenv) has been removed and some files (nw_tls.h 
and nw_sync.h) have been added into the build.  These files would change depending upon whether you were building on 6.4
.0 or 6.3.2.  We now determine the OS version from a system include file so a smoke build for these files isn't required
 any more.  What this means, is that, if you are building drivers, you have to remove the inclusion of the "sys/buildenv
/buildenv.mk" file in your driver common.mk file.  

  Hopefully this won't cause too much inconvenience.  Let me know if you run into problems.

   Robert.