When setting USE_GNU_TOOLS+= awk, sed, etc. the path to the respective
GNU tool is linked as awk, sed, etc., in the buildlink3 bin directory,
which is prepended to the shell path during package building.
Wouldn't it be a good idea to do the same thing for ${RM}, ${MKDIR},
${SED}, ${AWK}, etc. (if not overridden by USE_GNU_TOOLS)?
That way the respective tools would automatically be used with packages
that simply call rm, mkdir, sed, awk, etc.
On systems where the "native" tool in the path in not sufficiently
capable but some better tool has been explicitely configured (example:
${AWK} is set to nawk) that could make a difference for some packages
that need the additional capabilities.  

-- 
Georg Schwarz    http://home.pages.de/~schwarz/
 geos@epost.de     +49 177 8811442