pi@raspberrypi:/usr/local/src/FFmpeg $ sudo ./configure --arch=armel --target-os=linux --enable-gpl --enable-libx264 --enable-nonfree --enable-gnutls --extra-libs=-ldl --enable-zlib

....................ERROR: gnutls not found using pkg-config

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
[email protected] 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.