From Makefile.tpl: 
 
USUAL_AS_FOR_TARGET = ` \ 
  if [ -f $$r/gas/as-new ] ; then \ 
    echo $$r/gas/as-new ; \ 
... 
    if [ '$(host)' = '$(target)' ] ; then \ 
      echo $(AS); \ 
    else \ 
       echo as | sed '$(program_transform_name)' ; \ 
^^^^^^^^^^^^^^^ 
This isn't really what we're looking for, since program_transform_name is 
for the *newly built* tools, and the user may be supplying something weird, 
but it says nothing about where to find preexisting tools.  We should trust 
configure's choice, which is found using NCN_STRICT_TARGET_TOOL, and is 
essentially $(target_alias)-as (unless it was set by the user in some 
other way, of course). 
 
I have a patch for this already. 
 
     fi; \ 
   fi` 
 
Similarly for the other tools.  :-P