sdl/input.c:1657:8: error: ‘joystick0’ undeclared (first use in this function); did you mean ‘joystick’?
  if (! joystick0) return(AKEY_NONE);  /* no controller present */
        ^~~~~~~~~
        joystick
sdl/input.c:1657:8: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [Makefile:1021: sdl/input.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[2]: Leaving directory '/tmp/y/atari800-ATARI800_4_1_0/src'
make[1]: *** [Makefile:673: all] Error 2
make[1]: Leaving directory '/tmp/y/atari800-ATARI800_4_1_0/src'
make: *** [Makefile:415: all-recursive] Error 1