Use -Werror in build/make

* Remove unused local variables.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Iced5bb903902f49d7cd5cf5f572906a512c75e18
diff --git a/tools/zipalign/Android.bp b/tools/zipalign/Android.bp
index cfc6aec..2aa6450 100644
--- a/tools/zipalign/Android.bp
+++ b/tools/zipalign/Android.bp
@@ -13,6 +13,8 @@
         "ZipFile.cpp",
     ],
 
+    cflags: ["-Wall", "-Werror"],
+
     static_libs: [
         "libandroidfw",
         "libutils",