build fails

[obfusk]

Hi! I tried to build HideDroid from source, and the build fails with:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:mergeDexArmRelease'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade
   > com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: 
     Learn how to resolve the issue at https://developer.android.com/studio/build/dependencies#duplicate_classes.
     Type org.xmlpull.v1.util.XmlPullUtil is defined multiple times: /build/repo/app/build/intermediates/external_libs_dex/armRelease/mergeExtDexArmRelease/classes3.dex, /build/repo/app/build/intermediates/sub_project_dex_archive/armRelease/out/41c158fb4639c5a9cc0262b36887732dfd9c8619a1d70e374e9576bf4adb2c1a_1.jar:classes.dex

Can you tell me how you're avoiding that error when building?