I'm trying to run the configure file for glibc-2.20 I receive the error mentioned in the subject line. I tried altering the configure file like this:

case $ac_prog_version in
'') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
2.1[3-9]*)
ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
*) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

case $ac_prog_version in
'') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
2.1[3-9]*)
ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
*) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

to this:

case $ac_prog_version in
'') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
2.2[0-9]*)
ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
*) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

case $ac_prog_version in
'') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
2.2[0-9]*)
ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
*) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

which I found in a different post and it still failed. I'm using slackware-14.1-iso and LFS version 7.6. Any help would be greatly appreciated, thank you.

I fixed the issue by restoring from a snapshot back to the beginning of chapter 6 and going back through the steps that got me there. Not sure what I missed originally that might have caused the error but I've now moved beyond it. Hope that helps anyone else who may run into this same problem.