/usr/m68k-linux-gnu/include/sound/ is in linux-libc-dev-m68k-cross 4.15.0-18.19cross1.
This file is owned by root:root, with mode 0o755.
..
/usr/m68k-linux-gnu/include/sound/asequencer.h
/usr/m68k-linux-gnu/include/sound/asoc.h
/usr/m68k-linux-gnu/include/sound/asound.h
/usr/m68k-linux-gnu/include/sound/asound_fm.h
/usr/m68k-linux-gnu/include/sound/compress_offload.h
/usr/m68k-linux-gnu/include/sound/compress_params.h
/usr/m68k-linux-gnu/include/sound/emu10k1.h
/usr/m68k-linux-gnu/include/sound/firewire.h
/usr/m68k-linux-gnu/include/sound/hdsp.h
/usr/m68k-linux-gnu/include/sound/hdspm.h
/usr/m68k-linux-gnu/include/sound/sb16_csp.h
/usr/m68k-linux-gnu/include/sound/sfnt_info.h
/usr/m68k-linux-gnu/include/sound/snd_sst_tokens.h
/usr/m68k-linux-gnu/include/sound/tlv.h
/usr/m68k-linux-gnu/include/sound/usb_stream.h