Add ExperimentalBaseEncodingApi opt-in to test compiling tasks
diff --git a/libraries/stdlib/jdk7/build.gradle b/libraries/stdlib/jdk7/build.gradle
index 7af04e4..c3b98eb 100644
--- a/libraries/stdlib/jdk7/build.gradle
+++ b/libraries/stdlib/jdk7/build.gradle
@@ -80,6 +80,7 @@
             "-opt-in=kotlin.ExperimentalUnsignedTypes",
             "-opt-in=kotlin.ExperimentalStdlibApi",
             "-opt-in=kotlin.io.path.ExperimentalPathApi",
+            "-opt-in=kotlin.io.encoding.ExperimentalBaseEncodingApi",
             "-Xcommon-sources=${fileTree('../test').join(',')}",
             "-XXLanguage:+RangeUntilOperator",
     ]
diff --git a/libraries/stdlib/jdk8/build.gradle b/libraries/stdlib/jdk8/build.gradle
index fd23bb5..d0e3027 100644
--- a/libraries/stdlib/jdk8/build.gradle
+++ b/libraries/stdlib/jdk8/build.gradle
@@ -79,6 +79,7 @@
             "-opt-in=kotlin.ExperimentalUnsignedTypes",
             "-opt-in=kotlin.ExperimentalStdlibApi",
             "-opt-in=kotlin.io.path.ExperimentalPathApi",
+            "-opt-in=kotlin.io.encoding.ExperimentalBaseEncodingApi",
             "-Xcommon-sources=${fileTree('../test').join(',')}",
             "-XXLanguage:+RangeUntilOperator",
     ]
diff --git a/libraries/stdlib/jvm/build.gradle b/libraries/stdlib/jvm/build.gradle
index 3af86c3..bf534d7 100644
--- a/libraries/stdlib/jvm/build.gradle
+++ b/libraries/stdlib/jvm/build.gradle
@@ -176,6 +176,7 @@
                 "-opt-in=kotlin.RequiresOptIn",
                 "-opt-in=kotlin.ExperimentalUnsignedTypes",
                 "-opt-in=kotlin.ExperimentalStdlibApi",
+                "-opt-in=kotlin.io.encoding.ExperimentalBaseEncodingApi",
                 "-XXLanguage:+RangeUntilOperator",
         ]
         // This is needed for JavaTypeTest; typeOf for non-reified type parameters doesn't work otherwise, for implementation reasons.
diff --git a/libraries/stdlib/wasm/build.gradle.kts b/libraries/stdlib/wasm/build.gradle.kts
index 4138cd1..7017481 100644
--- a/libraries/stdlib/wasm/build.gradle.kts
+++ b/libraries/stdlib/wasm/build.gradle.kts
@@ -123,6 +123,7 @@
         "-opt-in=kotlin.RequiresOptIn",
         "-opt-in=kotlin.ExperimentalUnsignedTypes",
         "-opt-in=kotlin.ExperimentalStdlibApi",
+        "-opt-in=kotlin.io.encoding.ExperimentalBaseEncodingApi",
         "-XXLanguage:+RangeUntilOperator",
     )
 }
diff --git a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/StdlibTest.kt b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/StdlibTest.kt
index 741f248..c71c51c 100644
--- a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/StdlibTest.kt
+++ b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/StdlibTest.kt
@@ -20,7 +20,7 @@
     TC(
         name = "default",
         runnerType = TestRunnerType.DEFAULT,
-        freeCompilerArgs = [ENABLE_MPP, STDLIB_IS_A_FRIEND, ENABLE_X_STDLIB_API, ENABLE_RANGE_UNTIL],
+        freeCompilerArgs = [ENABLE_MPP, STDLIB_IS_A_FRIEND, ENABLE_X_STDLIB_API, ENABLE_X_BASE_ENCODING_API, ENABLE_RANGE_UNTIL],
         sourceLocations = [
             "libraries/stdlib/test/**.kt",
             "libraries/stdlib/common/test/**.kt",
@@ -33,7 +33,7 @@
     TC(
         name = "worker",
         runnerType = TestRunnerType.WORKER,
-        freeCompilerArgs = [ENABLE_MPP, STDLIB_IS_A_FRIEND, ENABLE_X_STDLIB_API, ENABLE_RANGE_UNTIL],
+        freeCompilerArgs = [ENABLE_MPP, STDLIB_IS_A_FRIEND, ENABLE_X_STDLIB_API, ENABLE_X_BASE_ENCODING_API, ENABLE_RANGE_UNTIL],
         sourceLocations = [
             "libraries/stdlib/test/**.kt",
             "libraries/stdlib/common/test/**.kt",
@@ -55,5 +55,6 @@
 private const val ENABLE_MPP = "-Xmulti-platform"
 internal const val STDLIB_IS_A_FRIEND = "-friend-modules=$KOTLIN_NATIVE_DISTRIBUTION/klib/common/stdlib"
 private const val ENABLE_X_STDLIB_API = "-opt-in=kotlin.ExperimentalStdlibApi"
+private const val ENABLE_X_BASE_ENCODING_API = "-opt-in=kotlin.io.encoding.ExperimentalBaseEncodingApi"
 private const val ENABLE_RANGE_UNTIL = "-XXLanguage:+RangeUntilOperator" // keep until 1.8
 private const val DISABLED_STDLIB_TEST = "test.collections.CollectionTest.abstractCollectionToArray"
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