Add Gradle Plugin Portal publication to the buildscripts

Add option to disable signing (-PnoSign), to be used when publishing
pre-built artifacts

Add option to define specific version for publishing, to be used when
publishing test versions

(cherry picked from commit dcd55e9)

libraries/tools/gradle-tools/build.gradle

@@ -4,9 +4,11 @@ buildscript {
 
     repositories {
         mavenCentral()
+        maven { url 'https://plugins.gradle.org/m2/' }
     }
     dependencies {
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlin_gradle_plugin_version}"
+        classpath "com.gradle.publish:plugin-publish-plugin:0.9.7"
     }
 }
 
@@ -45,4 +47,40 @@ task clean {
     doLast {
         delete "${buildDir}/repo"
     }
+}
+
+configure([project(':kotlin-gradle-plugin'), project(':kotlin-allopen'), project(':kotlin-noarg')]) { project ->
+    apply plugin: 'com.gradle.plugin-publish'
+
+    if (project.hasProperty('publishPluginsVersion')) {
+        configurations.archives.artifacts.all {
+            version = project.getProperty('publishPluginsVersion')
+        }
+    }
+
+    if (project.hasProperty("${project.name}-jar")) {
+        println("Using pre-built artifact for ${project.name}")
+        configurations.archives.artifacts.clear()
+
+        artifacts {
+            archives(file(project.getProperty("${project.name}-jar"))) {
+                name project.name
+            }
+        }
+    }
+
+    publishPlugins.doFirst {
+        assert !kotlin_version.contains('SNAPSHOT')
+    }
+
+    pluginBundle {
+        website = 'https://kotlinlang.org/'
+        vcsUrl = 'https://github.com/JetBrains/kotlin/'
+        description = 'Kotlin plugins for Gradle'
+        tags = ['kotlin']
+
+        mavenCoordinates {
+            groupId = "org.jetbrains.kotlin"
+        }
+    }
 }