Kapt: Add runtime library, move all modules inside the 'kapt3' directory

plugins/kapt3/kapt3-runtime/build.gradle.kts

@@ -0,0 +1,18 @@
+description = "Kotlin Annotation Processing Runtime"
+
+apply { plugin("kotlin") }
+
+jvmTarget = "1.6"
+
+sourceSets {
+    "main" { projectDefault() }
+    "test" {}
+}
+
+runtimeJar()
+sourcesJar()
+javadocJar()
+
+dist(targetName = "kotlin-annotation-processing-runtime.jar")
+
+publish()

plugins/kapt3/kapt3-runtime/src/KaptIgnored.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlinx.kapt
+
+/**
+ * Declaration annotated with [KaptIgnored] would not be included in stubs passed to annotation processors.
+ */
+@Target(AnnotationTarget.FUNCTION, AnnotationTarget.FIELD)
+@Retention(AnnotationRetention.SOURCE)
+public annotation class KaptIgnored