Tell the user about gnuplot if isn't installed.

git-svn-id: http://lm-sensors.org/svn/lm-sensors/branches/lm-sensors-3.0.0@5317 7894878c-1315-0410-8ee3-d5d059ff63e0

CHANGES

@@ -4,6 +4,7 @@ lm-sensors CHANGES file
 SVN-HEAD
   libsensors: Avoid namespace pollution
   fancontrol: Don't use named pipes when we don't need them (#2319)
+  pwmconfig: Tell the user about gnuplot if isn't installed
   sensors-detect: Add Intel SCH (bus) support
                   Add SMSC EMC6D103 support
                   Improve MAX6657, MAX6658, MAX6659 detection

prog/pwm/pwmconfig

@@ -330,6 +330,8 @@ function pwmdetail()
 		then
 			PLOT=y  	
 		fi
+	else
+		echo "Note: If you had $PLOTTER installed, I could generate a graphical plot."
 	fi
 
 	if [ "$PLOT" = "y" ]