Add example kernel module

examples/kernel-module/Makefile

@@ -0,0 +1,15 @@
+# out-of-tree called make with two arguments -- kernel headers path and name
+# of target binary that MUST be produced by makefile
+# e.g.:
+#    make KERNEL=/lib/modules/4.8.0-58-generic/build TARGET=hello-world.ko
+KERNEL := /lib/modules/$(shell uname -r)/build
+TARGET := out-of-tree-module-example
+
+obj-m += $(TARGET).o
+$(TARGET)-objs = module.o
+
+all:
+	make -C $(KERNEL) M=$(PWD) modules
+
+clean:
+	make -C $(KERNEL) M=$(PWD) clean