ERROR: libx264 not found

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 "config.log" produced by configure as this will help
solve the problem.
Makefile:637: recipe for target '/build/lede-17.01/slaves/phase2/arm_mpcore_vfp/build/sdk/build_dir/target-arm_mpcore+vfp_musl-1.1.16_eabi/ffmpeg-full/ffmpeg-3.2.2/.configured_fd6ef852d083d04226bd2efaae96f218' failed
make[3]: *** [/build/lede-17.01/slaves/phase2/arm_mpcore_vfp/build/sdk/build_dir/target-arm_mpcore+vfp_musl-1.1.16_eabi/ffmpeg-full/ffmpeg-3.2.2/.configured_fd6ef852d083d04226bd2efaae96f218] Error 1