Daniels-iMac:ffmpeg daniel$ ./configure --enable-cuda --enable-cuvid --enable-nvenc --enable-nonfree --enable-libnpp  --extra-cflags=-I/usr/local/cuda/include --extra-ldflags=-L/usr/local/cuda/lib
ERROR: cuda requested, but not all dependencies are satisfied: ffnvcodec

If you think configure made a mistake, make sure you are using the latest
version from Git.  If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "ffbuild/config.log" produced by configure as this will help
solve the problem.
Daniels-iMac:ffmpeg daniel$ pkg-config --cflags ffnvcodec
-I/usr/local/include
Daniels-iMac:ffmpeg daniel$ pkg-config ffnvcodec
Daniels-iMac:ffmpeg daniel$ echo $?
0
Daniels-iMac:ffmpeg daniel$ ls /usr/local/include/ffnvcodec/
dynlink_cuda.h		dynlink_cuviddec.h	dynlink_loader.h	dynlink_nvcuvid.h	nvEncodeAPI.h
Daniels-iMac:ffmpeg daniel$