title: Native libraries (*.so) files missing in the aar file(if dependent library is a shared library)
body: <p>I am Using Android Studio 1.5.1 Gradle version 2.8. Gradle experimental plugin v0.4.0
  I have a library with native C code and java code as well. I am generating a library CoreLib-fat-release.aar with native libraries for all architectures(libcore.so) - arm64-v8a, armeabi, armeabi-v7a, mips, mips64, x86, x86-64.
  I have a second library depending on my Core library. I made Core library as shared library. </p>
  
  <p>In second library gradle file:</p>
  
  <pre><code>jni {
              dependencies {
                  project ":CoreLib" buildType "release" productFlavor "fat" linkage "shared"
              }
      }
  </code></pre>
  
  <p>It is able to build properly, but when I open and see the second library aar file, I dont see libcore.so in all architecture folders.</p>
  
  <p>Eg: 
  SecondLibrary-fat-release.aar => SecondLibrary-fat-release-zip 
  Inside SecondLibrary-fat-release/jni folder, only x86 and x86_64 folder contains libcore.so file. Other folders (arm64-v8a, armeabi, armeabi-v7a, mips, mips64) doesnot contain libcore.so file. </p>
  
  <p>Because of this reason, if I use my Second Library in a 64 bit device, it is complaining UnSatisfiedLink error saying Found 32-bit library instead of 64-bit.</p>
  
  <p>HEre is my build.gradle of second library:</p>
  
  <pre><code>apply plugin: 'com.android.model.library'
  model {
  android {
      compileSdkVersion = 21
      buildToolsVersion = "23.0.2"
      defaultConfig.with {
          minSdkVersion.apiLevel = 21
          targetSdkVersion.apiLevel = 21
          testInstrumentationRunner = "android.test.InstrumentationTestRunner"
      }
      lintOptions.with {
          abortOnError = false
      }
  }
  android.ndk {
      moduleName = "secondlibrary
      cppFlags.addAll("-I${file(folder_path)}".toString(),
              "-I${file(sourcesDir +folder1)}".toString(),
              "-I${file(sourcesDir +folder2)}".toString(),
      )
      cppFlags.add("-frtti")
      cppFlags.add("-fexceptions")
      CFlags.addAll("-I${file(folder_path)}".toString(),
              "-I${file(sourcesDir +folder1)}".toString(),
              "-I${file(sourcesDir +folder2)}".toString(),
      )
      CFlags.add("-O3")
      CFlags.add("-funroll-loops")
      CFlags.add("-Wall")
      ldLibs.addAll(["android", "log", "stdc++", "c", "m", "z", "EGL", "GLESv2"])
      stl = "gnustl_shared"
  }
  // jni is the default dir; config this if yours is in different directory
  android.sources {
      androidTest {
          java {
              source {
                  srcDirs '../test_sources_path/src'
              }
          }
      }
      main {
          manifest {
              source {
                  srcDirs '.'
              }
          }
          java {
              source {
                  srcDir "src"
              }
          }
          jni {
              dependencies {
                  project ":CoreLib" buildType "release" productFlavor "fat" linkage "shared"
              }
              source {
                  srcDirs = ["jni",
                             path1,
                             path2,
                             "libcore.so"]
              }
          }
          jniLibs {
              dependencies {
                  library file(path_to_binaries + "libcore.so") abi "armeabi"
                  library file(path_to_binaries + "libcore.so") abi "x86"
                  library file(path_to_binaries + "libcore.so") abi "armeabi-v7a"
                  library file(path_to_binaries + "libcore.so") abi "mips"
                  library file(path_to_binaries + "libcore.so") abi "x86_64"
                  library file(path_to_binaries + "libcore.so") abi "arm64-v8a"
                  library file(path_to_binaries + "libcore.so") abi "mips64"
              }
          }
      }
  }
  android.productFlavors {
      create("fat")
  }
  repositories {
      libs(PrebuiltLibraries) {
          CoreLib {
              binaries.withType(SharedLibraryBinary) {
                  sharedLibraryFile = file(path_to_binaries + "${targetPlatform.getName()}/libcore.so")
              }
          }
      }
  }
   }
   dependencies {
       compile project(':CoreLib-fat-release')
   }
  </code></pre>
  
  <p>NOTE: If I make CoreLib linkage as 'static' instead of 'shared', then all libcore.so files are copied properly to all the folders.</p>
  
  <p>Please let me know if this is a programming issue or a bug in experimental plugin. Please suggest me if you know any alternative? Thank you.</p>