Download patch instead of requiring it to be installed

Part of work to make the code build on a clean Stretch machine.

Change-Id: I1f7b9b51a84a98bc178b05e575ae4b314cf69c1c
diff --git a/debian/patch.BUILD b/debian/patch.BUILD
new file mode 100644
index 0000000..93f8e7f
--- /dev/null
+++ b/debian/patch.BUILD
@@ -0,0 +1,5 @@
+filegroup(
+    name = "patch",
+    srcs = ["usr/bin/patch"],
+    visibility = ["//visibility:public"],
+)