Cómo arreglar los "símbolos no definidos" al compilar mplayer

Cuando intento compilar mplayer en MacOS (12.4) obtengo un error

Undefined symbols for architecture x86_64:
  "_x264_encoder_open_163", referenced from:
      _X264_init in libavcodec.a(libx264.o)
Undefined symbols for architecture x86_64:
  "_x264_encoder_open_163", referenced from:
      _X264_init in libavcodec.a(libx264.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mencoder] Error 1
make: *** Waiting for unfinished jobs....
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mplayer] Error 1

¿Alguna idea de cómo solucionar esto?

He corrido sólo

./configure

antes de eso.