build ffmper with x264 support for raspberry pi2

# Build environment. I use vagrant ubuntu/trusty64
sudo apt-get install build-essential git-core
sudo git clone https://github.com/raspberrypi/tools.git /opt/tools
export CCPREFIX="/opt/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-"

# Get ffmpeg and x264 repos
git clone git://source.ffmpeg.org/ffmpeg.git
cd ffmpeg
git clone git://git.videolan.org/x264

# Build x264

cd x264
configure --host=arm-linux --cross-prefix=${CCPREFIX} --enable-static --disable-asm
make
cd ..

# Build ffmpeg with x264

./configure --enable-cross-compile --cross-prefix=${CCPREFIX} --arch=armel --target-os=linux --enable-gpl --enable-libx264 --extra-cflags="-Ix264/" --extra-ldflags="-ldl -Lx264/"
make