Fix SL build

Author: kzu

Source/MethodCall.cs

@@ -188,15 +188,22 @@ private void SetFileInfo()
 				var mockAssembly = Assembly.GetExecutingAssembly();
 
 				// Move 'till we're at the entry point into Moq API
-				var frame = new StackTrace(true).GetFrames()
+#if !SILVERLIGHT
+				var frame = new StackTrace(true)
+#else
+				var frame = new StackTrace()
+#endif
+					.GetFrames()
 					.SkipWhile(f => f.GetMethod() != thisMethod)
 					.SkipWhile(f => f.GetMethod().DeclaringType == null || f.GetMethod().DeclaringType.Assembly == mockAssembly)
 					.FirstOrDefault();
 
 				if (frame != null)
 				{
 					this.FileLine = frame.GetFileLineNumber();
+#if !SILVERLIGHT
 					this.FileName = Path.GetFileName(frame.GetFileName());
+#endif
 					this.TestMethod = frame.GetMethod();
 				}
 			}