[Android] Set up an environment for C++ native ndk18

Ref: https://developer.android.com/studio/projects/add-native-code

Update app/build.gradle file

defaultConfig {
applicationId "com.nhancv.myapplication"
minSdkVersion 21
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
externalNativeBuild {
cmake {
cppFlags ""
}
}

}
buildTypes {
release {
minifyEnabled false…