title: FFmpeg installation on Raspberry Pi Zero W: Undefined references to __atomic
body: <p>I'm trying to install ffmpeg on my Raspberry Pi Zero W, but I get several error messages.</p>
  <p>OS: Raspberry Pi OS (32-bit) Lite (May 2020)</p>
  <p>I have executed the following commands:</p>
  <pre><code>sudo apt update
  sudo apt full-upgrade
  sudo apt install git
  git clone https://github.com/FFmpeg/FFmpeg.git
  cd FFmpeg
  ./configure --arch=armel --target-os=linux --enable-gpl --enable-omx --enable-omx-rpi --enable-nonfree
  make -j2
  sudo make install
  </code></pre>
  <p>Output of last command:</p>
  <pre><code>...
  LD      ffmpeg_g
  /usr/bin/ld: libavformat/libavformat.a(fifo.o): in function `fifo_init':
  /home/pi/FFmpeg/libavformat/fifo.c:519: undefined reference to `__atomic_store_8'
  /usr/bin/ld: libavformat/libavformat.a(fifo.o): in function `fifo_write_trailer':
  /home/pi/FFmpeg/libavformat/fifo.c:624: undefined reference to `__atomic_fetch_add_8'
  /usr/bin/ld: /home/pi/FFmpeg/libavformat/fifo.c:631: undefined reference to `__atomic_store_8'
  /usr/bin/ld: libavformat/libavformat.a(fifo.o): in function `fifo_thread_write_packet':
  /home/pi/FFmpeg/libavformat/fifo.c:188: undefined reference to `__atomic_fetch_sub_8'
  /usr/bin/ld: libavformat/libavformat.a(fifo.o): in function `fifo_consumer_thread':
  /home/pi/FFmpeg/libavformat/fifo.c:457: undefined reference to `__atomic_load_8'
  /usr/bin/ld: libavformat/libavformat.a(fifo.o): in function `fifo_write_packet':
  /home/pi/FFmpeg/libavformat/fifo.c:597: undefined reference to `__atomic_fetch_add_8'
  collect2: error: ld returned 1 exit status
  make: *** [Makefile:114: ffmpeg_g] Error 1
  </code></pre>
  <p>Maybe another package is missing? Do I have to change anything in the config?</p>