launch ndk-build from build-gradle in Android project

build.gradle

apply plugin: 'com.android.application'
android {
    compileSdkVersion 28
    buildToolsVersion "28.0.0"
    defaultConfig {
        applicationId "com.example.ndkbuildexample"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
    }

    externalNativeBuild {
      ndkBuild {
        path 'src/main/jni/Android.mk'
      }
    }

    buildTypes {
        debug {
            debuggable true
        }
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:multidex:1.0.3'
}