kdenetwork 3.5.13: -DBUILD_WIFI=OFF

I am unable to build kdenetwork 3.5.13 from the source tarballs on Slackware 13.1 unless I use the -DBUILD_WIFI=OFF option. The error message: -- Looking for iw_get_stats in iw -- Looking for iw_get_stats in iw - not found CMake Error at cmake/modules/TDEMacros.cmake:20 (message): ################################################# wifi support needs wireless tools >= 27, but was not found on your system Slackware 13.1 has wireless-tools-29 and the package is installed in my build environment. There is a /usr/sbin/iw command installed. I want to build the package to support wireless. How do I get around this error? Thanks. Darrell