Allow IR-less klibs, fix failures when no IR is produced

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/CompilerOutput.kt

@@ -153,7 +153,7 @@ internal fun produceOutput(context: Context) {
                     context.config.includeBinaries,
                     neededLibraries,
                     context.serializedMetadata!!,
-                    context.serializedIr!!,
+                    context.serializedIr,
                     versions,
                     target,
                     output,

shared/src/library/kotlin/org/jetbrains/kotlin/konan/library/impl/KonanLibraryWriterImpl.kt

@@ -44,7 +44,7 @@ fun buildLibrary(
     included: List<String>,
     linkDependencies: List<KonanLibrary>,
     metadata: SerializedMetadata,
-    ir: SerializedIrModule,
+    ir: SerializedIrModule?,
     versions: KotlinLibraryVersioning,
     target: KonanTarget,
     output: String,
@@ -57,7 +57,9 @@ fun buildLibrary(
     val library = KonanLibraryWriterImpl(File(output), moduleName, versions, target, nopack)
 
     library.addMetadata(metadata)
-    library.addIr(ir)
+    if (ir != null) {
+        library.addIr(ir)
+    }
 
     natives.forEach {
         library.addNativeBitcode(it)