Fix couple compiler warnings.

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt

@@ -313,8 +313,8 @@ fun buildNativeIndexImpl(headerFile: File, args: List<String>): NativeIndex {
                 importedASTFile.value = null
                 startedTranslationUnit.value = null
                 indexDeclaration.value = staticCFunction { clientData, info ->
-                    val index = StableObjPtr.fromValue(clientData!!).get() as NativeIndexImpl
-                    index.indexDeclaration(info!!.pointed)
+                    val nativeIndex = StableObjPtr.fromValue(clientData!!).get() as NativeIndexImpl
+                    nativeIndex.indexDeclaration(info!!.pointed)
                 }
                 indexEntityReference.value = null
             }

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/main.kt

@@ -87,8 +87,8 @@ private fun Properties.getSpaceSeparated(name: String): List<String> {
 }
 
 private fun List<String>?.isTrue(): Boolean {
-    // The rightmost wins
-    return this?.last() == "true" ?: false
+    // The rightmost wins, null != "true".
+    return this?.last() == "true"
 }
 
 private fun processLib(ktGenRoot: String,

runtime/src/main/cpp/ToString.cpp

@@ -51,7 +51,7 @@ KString Kotlin_Int_toString(KInt value) {
 
 KString Kotlin_Long_toString(KLong value) {
   char cstring[32];
-  snprintf(cstring, sizeof(cstring), "%lld", value);
+  snprintf(cstring, sizeof(cstring), "%lld", static_cast<long long>(value));
   return makeString(cstring);
 }