check_warn = $(if $(filter-out undefined,$(origin F_$(1))),$(filter ,$(shell $(call F_$(1),$(2),$(3),$(4)) >&2)),$(check_warn_nofix))
endif
check_warn = $(if $(filter-out undefined,$(origin F_$(1))),$(filter ,$(shell $(call F_$(1),$(2),$(3),$(4)) >&2)),$(check_warn_nofix))
endif