Merge "Write product config files only if changed."
diff --git a/android/config.go b/android/config.go
index 600fda0..bb3cc97 100644
--- a/android/config.go
+++ b/android/config.go
@@ -397,11 +397,13 @@
 arch_variant_product_var_constraints = _arch_variant_product_var_constraints
 `,
 	}
-	err = os.WriteFile(filepath.Join(dir, "product_variables.bzl"), []byte(strings.Join(bzl, "\n")), 0644)
+	err = pathtools.WriteFileIfChanged(filepath.Join(dir, "product_variables.bzl"),
+		[]byte(strings.Join(bzl, "\n")), 0644)
 	if err != nil {
 		return fmt.Errorf("Could not write .bzl config file %s", err)
 	}
-	err = os.WriteFile(filepath.Join(dir, "BUILD"), []byte(bazel.GeneratedBazelFileWarning), 0644)
+	err = pathtools.WriteFileIfChanged(filepath.Join(dir, "BUILD"),
+		[]byte(bazel.GeneratedBazelFileWarning), 0644)
 	if err != nil {
 		return fmt.Errorf("Could not write BUILD config file %s", err)
 	}