bison version check error: "./configure: bad math expression: unbalanced stack"

[R Blake]

bison configure reports version check errors at:

(initial config)
.....
checking for bison... bison -y
checking bison version... ./configure: bad math expression: unbalanced 
stack [14411]
checking for flex... flex
.....

and,

(Configuring Zend)
.....
checking bison version... ./configure: bad math expression: unbalanced 
stack [99981]
checking for limits.h... (cached) yes
checking malloc.h usability... yes
.....

in both cases, the culprit seems to be the following test for Bison version 
in configure:

echo $ECHO_N "checking bison version... $ECHO_C" >&6
   set `bison --version| grep 'GNU Bison' | cut -d ' ' -f 4 | sed -e 
's/\./ /'`
   if test "${1}" = "1" -a "${2}" -lt "28"; then
       { echo "$as_me:$LINENO: WARNING: You will need bison 1.28 if you 
want to
echo "$as_me: WARNING: You will need bison 1.28 if you want to regenerate 
the Ze

note that

> bison --version| grep 'GNU Bison' | cut -d ' ' -f 4 | sed -e 's/\./ /'

reports back:

> 1 49a


richard