You appear to be compiling the NVIDIA kernel module with
a compiler different from the one that was used to compile
the running kernel. This may be perfectly fine, but there
are cases where this can lead to unexpected behaviour and
If you know what you are doing and want to override this
check, you can do so by setting IGNORE_CC_MISMATCH.
In any other case, set the CC environment variable to the
name of the compiler that was used to compile the kernel.
[1;31m*** Failed cc sanity check. Bailing out! ***
[0mmake: *** [gcc-check] Error 1
The compiler is failing the sanity check for YOUR sake, so its obvious why it doesn't work now instead of later on. It should work if you ignore the cc mismatch in this case however.
and off it goes a building your purty nice new module. Enjoy Fedora.
Remember to set your X driver to nvidia in that XF86Config.