Documentation/video4linux/Makefile - kernel/msm-4.9 - Gitiles

 # kbuild trick to avoid linker error. Can be omitted if a module is built.
 obj- := dummy.o

 # List of programs to build
 hostprogs-y := v4lgrab

 # Tell kbuild to always build the programs
 always := $(hostprogs-y)
	# kbuild trick to avoid linker error. Can be omitted if a module is built.
	obj- := dummy.o

	# List of programs to build
	hostprogs-y := v4lgrab

	# Tell kbuild to always build the programs
	always := $(hostprogs-y)