--extra-cflags=-I/xxxx/include
第三方库不在默认的include路径，则需要指定--extra-cflags=-I/xxxx/include
--extra-ldflags=-L/usr/local/x264-x86/lib
如下指定多个：
./configure --prefix=/usr/local/ffmpeg --enable-libmp3lame --enable-libvorbis --enable-shared --extra-cflags="-I/usr/local/lame/include -I/usr/local/libvorbis/include -I/usr/local/libogg/include" --extra-ldflags="-L/usr/local/lame/lib -L/usr/local/libvorbis/lib -L/usr/local/libogg/lib"