title: cant build unity project with both facebook sdk and audiance network sdk in it
body: <p>When I import both audience network sdk and facebook sdk in my unity project it fails to build the project.</p>
  
  <p>I tried deleting all unity packages using package manager.  </p>
  
  <p>updated jdk8_11 and ndk16b  </p>
  
  <p>updated unity to 2019.1.9  </p>
  
  <p>But nothing worked</p>
  
  <p>I know the problem lies within facebook and not unity or anything else because  </p>
  
  <ol>
  <li><p>project builds just fine with just audience network sdk in it.    </p></li>
  <li><p>project builds just fine with just facebook sdk in it.</p></li>
  </ol>
  
  <p>The Build fails only when I import both the packages in the project.</p>
  
  <p>I get following error when I import both package in unity:  </p>
  
  <blockquote>
    <p>PrecompiledAssemblyException: Multiple precompiled assemblies with the
    same name Facebook.Unity.Android.dll included for the current
    platform. Only one assembly with the same name is allowed per
    platform. Assembly path: {0}
    UnityEditor.Scripting.ScriptCompilation.EditorBuildRules.CreateTargetAssemblies
    (System.Collections.Generic.IEnumerable<code>1[T] customScriptAssemblies,
    System.Collections.Generic.IEnumerable</code>1[T] precompiledAssemblies) (at
    C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorBuildRules.cs:221)
    UnityEditor.Scripting.ScriptCompilation.EditorCompilation.UpdateCustomTargetAssemblies
    () (at
    C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorCompilation.cs:672)
    UnityEditor.Scripting.ScriptCompilation.EditorCompilation.SetAllCustomScriptAssemblyJsonContents
    (System.String[] paths, System.String[] contents, System.String[]
    guids) (at
    C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorCompilation.cs:892)
    UnityEditor.Scripting.ScriptCompilation.EditorCompilationInterface.SetAllCustomScriptAssemblyJsonContents
    (System.String[] allAssemblyJsonPaths, System.String[]
    allAssemblyJsonContents, System.String[] guids) (at
    C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorCompilationInterface.cs:241)</p>
  </blockquote>