diff --git a/tools/atree/Android.bp b/tools/atree/Android.bp
index 3c3a8ef..5fbe042 100644
--- a/tools/atree/Android.bp
+++ b/tools/atree/Android.bp
@@ -9,5 +9,6 @@
         "files.cpp",
         "fs.cpp",
     ],
+    cflags: ["-Wall", "-Werror"],
     static_libs: ["libhost"],
 }
diff --git a/tools/atree/files.cpp b/tools/atree/files.cpp
index d945f58..d5c8a97 100644
--- a/tools/atree/files.cpp
+++ b/tools/atree/files.cpp
@@ -425,8 +425,6 @@
                 const vector<string>& excludes,
                 vector<FileRecord>* more)
 {
-    int err;
-
     string full = path_append(rec.sourceBase, rec.sourceName);
     full = path_append(full, path);