os::exit and os::fastexit added.

lib/std/os/os.c3

@@ -0,0 +1,27 @@
+module std::os;
+import libc;
+
+<*
+ Exit the process with a given exit code. This will typically call 'exit' in LibC
+*>
+fn void exit(int result, bool cleanup = true) @weak
+{
+	$if env::LIBC:
+		libc::exit(result);
+	$else
+		$$trap();
+	$endif
+}
+
+<*
+ Exit the process with a given exit code. This will typically call '_Exit' in LibC
+ usually bypassing '@finalizer' functions.
+*>
+fn void fastexit(int result, bool cleanup = true) @weak
+{
+	$if env::LIBC:
+		libc::_exit(result);
+	$else
+		$$trap();
+	$endif
+}