[BusyBox] Why glibc doesn't like busybox sed.

[Rob Landley]

So here's the snippet in the ./configure file for glibc-2.3.2 that's rejecting 
busybox's sed (modulo cut and past wordwrap/whitespace damage):

  # Found it, now check the version.
  echo "$as_me:$LINENO: checking version of $SED" >&5
echo $ECHO_N "checking version of $SED... $ECHO_C" >&6
  ac_prog_version=`$SED --version 2>&1 | sed -n 's/^.*GNU sed version 
\([0-9]*\.[0-9.]*\).*$/\1/p'`
  case $ac_prog_version in
    '') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
    3.0[2-9]*|3.[1-9]*|[4-9]*)
       ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
    *) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

Notice that in order for us to fake out this test, we would have to reply with 
the string "GNU sed version 3.1".  I.E. we have to claim to not only be a 
Sed, but to specifically be _GNU_ sed.  A fully compatible sed implementation 
isn't sufficient, they test for their brand of cola.

I think the correct fix here is to shoot this test in the head with a bazooka 
full of broken glass and rusty nails.  Opinions?

Rob