arch/x86/include/uapi/asm/Kbuild - third_party/linux - Git at Google

 # UAPI Header export list
 include include/uapi/asm-generic/Kbuild.asm

 generated-y += unistd_32.h
 generated-y += unistd_64.h
 generated-y += unistd_x32.h
	# UAPI Header export list
	include include/uapi/asm-generic/Kbuild.asm

	generated-y += unistd_32.h
	generated-y += unistd_64.h
	generated-y += unistd_x32.h