nagios-plugins-1.4.15 Install Problem on Solaris 10

I am trying to install nagios-plugins-1.4.15 on a Solaris 10 box and when I run the ./configure script I get this error:

checking for grep that handles long lines and -e... configure: error: no acceptable grep could be found in /usr/local/bin:/usr/local/sbin:/usr/sfw/bin:/usr/bin:/sbin:/usr/sbin:/opt/VRTSob/bin:/opt/VRTSvxfs/sbin:/opt/VRTS/install:/etc/vx/bin:/opt/SUNWppro/bin:/usr/cluster/bin:/usr/openv/netbackup/bin:/usr/openv/netbackup/bin/admincmd:/usr/openv/netbackup/bin/goodies:/usr/openv/volmgr/bin:/usr/xpg4/bin

What do I need to install? All the grep commands, egrep, fgrep and grep and located in /usr/bin

I think it requires /usr/xpg4/bin/grep.
check it is installed or not. if is not installed , install SUNWxcu4 package and then resume your setup.

regards
ygemici

Thank you, I will try that