v4.19.13 snapshot.
diff --git a/tools/gpio/Build b/tools/gpio/Build
new file mode 100644
index 0000000..620c193
--- /dev/null
+++ b/tools/gpio/Build
@@ -0,0 +1,3 @@
+lsgpio-y += lsgpio.o gpio-utils.o
+gpio-hammer-y += gpio-hammer.o gpio-utils.o
+gpio-event-mon-y += gpio-event-mon.o gpio-utils.o