cc-c-option = $(if $(shell $(CC) $1 $2 -c -o /dev/null -xc /dev/null \
>/dev/null 2>&1 && echo OK), $2, $3)
-VPATH_SUFFIXES = %.c %.h %.S %.cc %.cpp %.m %.mak %.texi %.sh %.rc
+VPATH_SUFFIXES = %.c %.h %.S %.cc %.cpp %.m %.mak %.texi %.sh %.rc Kconfig%
set-vpath = $(if $1,$(foreach PATTERN,$(VPATH_SUFFIXES),$(eval vpath $(PATTERN) $1)))
# install-prog list, dir