clean up locking

veilid-flutter/example/android/app/build.gradle

@@ -41,13 +41,6 @@ android {
         main.java.srcDirs += 'src/main/kotlin'
     }
 
-
-    // xxx why does backtrace not work in android?
-    // tried this but it doesn't help
-    // packagingOptions {
-    //     jniLibs.useLegacyPackaging = true
-    // }
-
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.veilid.veilid_example"
@@ -63,6 +56,12 @@ android {
             // Signing with the debug keys for now, so `flutter run --release` works.
             signingConfig signingConfigs.debug
         }
+        debug {
+            packagingOptions {
+                jniLibs.useLegacyPackaging = true
+                jniLibs.keepDebugSymbols += '**/libveilid_flutter.so'
+            }
+        }
     }
 }