Add diff_target_files tool

Add a tool that lists files that have changed between two builds by
comparing the target-files.zip artifacts.

Bug: 121158314
Test: unit tests
Change-Id: I3ca5dd1fdf652dffef923ad7307fd71e49e2e95a
diff --git a/cmd/diff_target_files/Android.bp b/cmd/diff_target_files/Android.bp
new file mode 100644
index 0000000..5397f4b
--- /dev/null
+++ b/cmd/diff_target_files/Android.bp
@@ -0,0 +1,16 @@
+blueprint_go_binary {
+    name: "diff_target_files",
+    srcs: [
+        "compare.go",
+        "diff_target_files.go",
+        "glob.go",
+        "target_files.go",
+        "whitelist.go",
+        "zip_artifact.go",
+    ],
+    testSrcs: [
+        "compare_test.go",
+        "glob_test.go",
+        "whitelist_test.go",
+    ],
+}