Set default jvmTarget when creating new Gradle project

jvmTarget "1.8" is required to be able to use inline functions from
kotlin-stdlib-jre8.

idea/src/org/jetbrains/kotlin/idea/configuration/GradleKotlinFrameworkSupportProvider.kt

@@ -24,6 +24,7 @@ import com.intellij.openapi.roots.ModifiableRootModel
 import org.jetbrains.kotlin.idea.KotlinIcons
 import org.jetbrains.kotlin.idea.versions.MAVEN_JS_STDLIB_ID
 import org.jetbrains.kotlin.idea.versions.bundledRuntimeVersion
+import org.jetbrains.kotlin.idea.versions.getDefaultJvmTarget
 import org.jetbrains.plugins.gradle.frameworkSupport.BuildScriptDataBuilder
 import org.jetbrains.plugins.gradle.frameworkSupport.GradleFrameworkSupportProvider
 import javax.swing.Icon
@@ -77,6 +78,15 @@ class GradleKotlinJavaFrameworkSupportProvider : GradleKotlinFrameworkSupportPro
 
     override fun getRuntimeLibrary(rootModel: ModifiableRootModel) =
             KotlinWithGradleConfigurator.getRuntimeLibraryForSdk(rootModel.sdk, bundledRuntimeVersion())
+
+    override fun addSupport(module: Module, rootModel: ModifiableRootModel, modifiableModelsProvider: ModifiableModelsProvider, buildScriptData: BuildScriptDataBuilder) {
+        super.addSupport(module, rootModel, modifiableModelsProvider, buildScriptData)
+        val jvmTarget = getDefaultJvmTarget(rootModel.sdk, bundledRuntimeVersion())
+        if (jvmTarget != null) {
+            buildScriptData.addOther("compileKotlin {\n    kotlinOptions.jvmTarget = \"1.8\"\n}\n\n")
+            buildScriptData.addOther("compileTestKotlin {\n    kotlinOptions.jvmTarget = \"1.8\"\n}\n")
+        }
+    }
 }
 
 class GradleKotlinJSFrameworkSupportProvider : GradleKotlinFrameworkSupportProvider("KOTLIN_JS", "Kotlin (JavaScript)") {

idea/src/org/jetbrains/kotlin/idea/versions/KotlinRuntimeLibraryUtil.kt

@@ -41,6 +41,7 @@ import com.intellij.util.indexing.FileBasedIndex
 import com.intellij.util.indexing.ScalarIndexExtension
 import com.intellij.util.text.VersionComparatorUtil
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.config.JvmTarget
 import org.jetbrains.kotlin.idea.KotlinPluginUtil
 import org.jetbrains.kotlin.idea.configuration.*
 import org.jetbrains.kotlin.idea.framework.JavaRuntimeDetectionUtil
@@ -344,6 +345,17 @@ fun getStdlibArtifactId(sdk: Sdk?, version: String): String {
     return artifactId
 }
 
+fun getDefaultJvmTarget(sdk: Sdk?, version: String): JvmTarget? {
+    if (!hasJreSpecificRuntime(version)) {
+        return null
+    }
+    val sdkVersion = sdk?.let { JavaSdk.getInstance().getVersion(it) }
+    if (sdkVersion != null && sdkVersion.isAtLeast(JavaSdkVersion.JDK_1_8)) {
+        return JvmTarget.JVM_1_8
+    }
+    return null
+}
+
 fun hasJreSpecificRuntime(version: String): Boolean =
         VersionComparatorUtil.compare(version, "1.1.0") >= 0 ||
         isSnapshot(version) ||