Precompile ndk files.

android/build.gradle

@@ -9,13 +9,12 @@ android {
         targetSdkVersion 23
         versionCode 1
         versionName "1.0"
-
-        ndk {
-            moduleName "rnupdate"
-            ldLibs "log"
-            abiFilters "armeabi-v7a", "x86"
+    }
+    sourceSets {
+        main {
+            // let gradle pack the shared library into apk
+            jniLibs.srcDirs = ['./lib']
         }
-
     }
 }