FWIW, I was recently browsing some configure file, and saw that IFS was used, and then defined afterward. I can't seem to resurrect my old CVS checkout, so I can't tell if the trouble persists currently, but that should be easy to check. Cheers!
~/src/texinfo % grep -w IFS configure | sed 6q nostromo 16:08
*) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
IFS=$as_save_IFS
as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
IFS=$as_save_IFS
# IFS
IFS=" $as_nl"
