Debian Lenny has a very recent GCC Compiler for those who wish to build things with the latest and greatest, which is v4.3 something or other. On the other hand, the kernel is built with GCC 4.1. Kernel modules, as a result need to be built with GCC 4.1. The VMWare tools are one example of this requirement.
I've finally figured out what the CC environment variable can be used for. By keeping gcc-4.3 as a standard default, one can use 'export CC=gcc-4.1' to make use of the older GCC v4.1 compiler for compiling kernel modules.