And what did you get when you didn't have IGNORE_CC_MISMATCH set? Did you read the ramifications (in the README, one of the appendices) of setting it before you did it? The way that using it can (and very likely will) cause major problems inside the kernel once the kernel module loads?
The nforce driver apparently doesn't use the same build system as the nVidia one. Either that, or Mandrake's gcc is terminally braindead (either one is very possible), and it searches the system include directories first. What it should do is search the -I directories first (the one that was given to it was /usr/src/linux-<version>/include, you will notice), and then the system include directories if it can't find something.
SOOOO... are there files in /usr/include/linux-<version>/include/linux?
You notice the filenames that are giving errors -- /usr/include/linux/something? These are never supposed to be used in a module, only in user programs. They don't even have to correspond to your current kernel (actually, they almost NEVER should correspond to your current kernel, but rather the one that you compiled glibc against). Modules will not work when compiled against them -- and the big long list of errors is Mandrake's way of telling you that. You're going to have to do something so that the compiler looks in the right place for the include files. That can be either making sure they exist in the right place, or moving the other ones somewhere else, or something similar.