build fails when yadif videotoolbox is desired

with 6.1.1 (also tried latest 7.0)

BIN2C	libavfilter/metal/vf_yadif_videotoolbox.metallib.c
/bin/sh: line 1: 60448 Killed: 9               ffbuild/bin2c libavfilter/metal/vf_yadif_videotoolbox.metallib libavfilter/metal/vf_yadif_videotoolbox.metallib.c vf_yadif_videotoolbox_metallib
make: *** [libavfilter/metal/vf_yadif_videotoolbox.metallib.c] Error 137