stdlib: Add exitProcess function

backend.native/tests/build.gradle

@@ -408,6 +408,11 @@ task array_to_any(type: RunKonanTest) {
     source = "codegen/basics/array_to_any.kt"
 }
 
+task runtime_basic_exit(type: RunKonanTest) {
+    source = "runtime/basic/exit.kt"
+    expectedExitStatus = 42
+}
+
 task hello0(type: RunKonanTest) {
     goldValue = "Hello, world!\n"
     source = "runtime/basic/hello0.kt"

backend.native/tests/runtime/basic/exit.kt

@@ -0,0 +1,5 @@
+import kotlin.system.*
+
+fun main(args: Array<String>) {
+    exitProcess(42)
+}

runtime/src/main/cpp/Natives.cpp

@@ -66,4 +66,8 @@ void Kotlin_interop_free(void* ptr) {
   konan::free(ptr);
 }
 
+void Kotlin_system_exitProcess(KInt status) {
+  exit(status);
+}
+
 }  // extern "C"

runtime/src/main/kotlin/kotlin/system/Process.kt

@@ -0,0 +1,11 @@
+package kotlin.system
+
+/**
+ * Terminates the currently running process.
+ * The argument serves as a status code; by convention,
+ * a nonzero status code indicates abnormal termination.
+ *
+ * This method never returns normally.
+ */
+@SymbolName("Kotlin_system_exitProcess")
+public external fun exitProcess(status: Int): Nothing