+The Mono C# compiler by default only references three assemblies:
+mscorlib.dll, System.dll and System.Xml.dll. If you want to
+reference extra libraries you must manually specify them using the
+-pkg: command line option or the -r: command line option.
+Alternatively if you want to get all of the System libraries, you can
+use the -pkg:dotnet command line option.
+.PP