There is no real need to upgrade your GCC, just because you think you should install the latest release of ndiswrapper. If you are running Slackware 10.2 (which I consider a "recent Slackware" for a first-time user) you can still use ndiswrapper 1.14 with your 2.4 kernel - or 1.15 if you installed a 2.6 kernel afterwards. Those two version numbers are the highest you can still compile on Slackware 10.2 without having to upgrade the GCC. Try it out, and if it works with your network hardware, then I would not worry about needing the latest ndiswrapper release.
Packages and the SlackBuild (build script) can be found here:
http://www.slackware.com/~alien/slac...pper/pkg/10.2/
Slackware "current" (the soon to become Slackware 11.0) comes with a newer version of GCC and can compile the latest ndiswrapper source code just fine. It might take less work and effort to just wait for Slackware 11 to be released, upgrade, and then install the latest & greatest ndiswrapper.
By the way, you didn't tell what network hardware you have, that is supposedly not supported by any other driver but ndiswrapper...
Eric