Migrate to AndroidX and Gradle Kotlin DSL

Also updates Kotlin to 1.3.31, kotlinx.coroutines to 1.2.1,
Gradle to 5.4.1 and Splitties to 3.0.0-alpha06

build.gradle.kts

@@ -0,0 +1,13 @@
+@file:Suppress("SpellCheckingInspection")
+
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+allprojects {
+    repositories {
+        setupForProject()
+    }
+}
+
+task<Delete>("clean") {
+    delete(rootProject.buildDir)
+}

buildSrc/build.gradle.kts

@@ -0,0 +1,32 @@
+plugins {
+    `kotlin-dsl`
+}
+
+repositories {
+    google()
+    jcenter()
+    maven(url = "https://dl.bintray.com/kotlin/kotlin-eap")
+}
+
+val kotlinVersion = "1.3.31" // Don't forget to update in Dependencies.kt too!
+
+dependencies {
+    compileOnly(gradleApi())
+    implementation("com.android.tools.build:gradle:3.5.0-alpha13")
+    implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion")
+    implementation("com.jfrog.bintray.gradle:gradle-bintray-plugin:1.8.4")
+}
+
+configurations.all {
+    val isKotlinCompiler = name == "embeddedKotlin" ||
+            name.startsWith("kotlin") ||
+            name.startsWith("kapt")
+    if (!isKotlinCompiler) {
+        resolutionStrategy.eachDependency {
+            @Suppress("UnstableApiUsage")
+            if (requested.group == "org.jetbrains.kotlin" &&
+                requested.module.name == "kotlin-compiler-embeddable"
+            ) useVersion(kotlinVersion)
+        }
+    }
+}

buildSrc/src/main/kotlin/AndroidLibraryConfig.kt

@@ -0,0 +1,29 @@
+import org.gradle.api.Action
+import com.android.build.gradle.LibraryExtension as AndroidLibraryExtension
+
+fun AndroidLibraryExtension.setDefaults() {
+    compileSdkVersion(ProjectVersions.androidSdk)
+    buildToolsVersion(ProjectVersions.androidBuildTools)
+    defaultConfig {
+        minSdkVersion(14)
+        targetSdkVersion(ProjectVersions.androidSdk)
+        versionCode = 1
+        versionName = ProjectVersions.thisLibrary
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        getByName("release") {
+            isMinifyEnabled = false
+        }
+    }
+    sourceSets.getByName("main") {
+        manifest.srcFile("src/androidMain/AndroidManifest.xml")
+        res.srcDir("src/androidMain/res")
+    }
+    // TODO replace with https://issuetracker.google.com/issues/72050365 once released.
+    libraryVariants.all(Action {
+        generateBuildConfigProvider.configure {
+            enabled = false
+        }
+    })
+}

buildSrc/src/main/kotlin/BintrayUpload.kt

@@ -0,0 +1,55 @@
+@file:Suppress("UnusedImport") // Needed for delegates imports to not be removed by the IDE.
+
+import com.android.build.gradle.internal.tasks.factory.dependsOn
+import com.jfrog.bintray.gradle.BintrayExtension
+import org.codehaus.groovy.runtime.ProcessGroovyMethods
+import org.gradle.api.Project
+import org.gradle.api.Task
+import org.gradle.api.publish.PublishingExtension
+import org.gradle.api.tasks.TaskProvider
+import org.gradle.kotlin.dsl.closureOf
+import org.gradle.kotlin.dsl.existing
+import org.gradle.kotlin.dsl.getValue
+import org.gradle.kotlin.dsl.provideDelegate
+
+fun BintrayExtension.setupPublicationsUpload(
+    project: Project,
+    publishing: PublishingExtension,
+    skipMetadataPublication: Boolean = false,
+    skipMultiplatformPublication: Boolean = skipMetadataPublication
+) {
+    val bintrayUpload: TaskProvider<Task> by project.tasks.existing
+    val publishToMavenLocal: TaskProvider<Task> by project.tasks.existing
+    bintrayUpload.dependsOn(publishToMavenLocal)
+    if (!isDevVersion) {
+        project.checkNoVersionRanges()
+        bintrayUpload.configure {
+            doFirst {
+                val gitTag = ProcessGroovyMethods.getText(
+                    Runtime.getRuntime().exec("git describe --dirty")
+                ).trim()
+                val expectedTag = "v${ProjectVersions.thisLibrary}"
+                if (gitTag != expectedTag) error("Expected git tag '$expectedTag' but got '$gitTag'")
+            }
+        }
+    }
+    user = project.findProperty("beepiz_bintray_user") as String?
+    key = project.findProperty("beepiz_bintray_api_key") as String?
+    val publicationNames: Array<String> = publishing.publications.filterNot {
+        skipMetadataPublication && it.name == "metadata" ||
+                skipMultiplatformPublication && it.name == "kotlinMultiplatform"
+    }.map { it.name }.toTypedArray()
+    setPublications(*publicationNames)
+    pkg(closureOf<BintrayExtension.PackageConfig> {
+        repo = if (isDevVersion) "maven-dev" else "maven"
+        name = "blegattcoroutines"
+        desc = Publishing.libraryDesc
+        websiteUrl = Publishing.siteUrl
+        issueTrackerUrl = "https://github.com/Beepiz/BleGattCoroutines/issues"
+        vcsUrl = Publishing.gitUrl
+        setLicenses("Apache-2.0")
+        publicDownloadNumbers = true
+        githubRepo = "Beepiz/BleGattCoroutines"
+        publish = isDevVersion
+    })
+}