Add enable / disable feature in Maven project

Part of KT-26775

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CliArgumentStringBuilder.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.cli.common.arguments
+
+import org.jetbrains.kotlin.config.LanguageFeature
+
+object CliArgumentStringBuilder {
+    const val languagePrefix = "-XXLanguage:"
+
+    private val LanguageFeature.State.sign: String
+        get() = when (this) {
+            LanguageFeature.State.ENABLED -> "+"
+            LanguageFeature.State.DISABLED -> "-"
+            LanguageFeature.State.ENABLED_WITH_WARNING -> "+" // not supported normally
+            LanguageFeature.State.ENABLED_WITH_ERROR -> "-" // not supported normally
+        }
+
+    fun LanguageFeature.buildArgumentString(state: LanguageFeature.State): String {
+        return "$languagePrefix${state.sign}$name"
+    }
+}