'roundf()' wasn't introduced in MSVC until VS2013 - so for the time being, let's emulate it using 'floorf()'

libs/pbd/msvc/msvc_pbd.cc

@@ -223,6 +223,24 @@ ssize_t ret;
 	return (ret);
 }
 
+//***************************************************************
+//
+//	roundf()
+//
+// Emulates roundf() using floorf().
+//
+//	Returns:
+//
+//    On Success: The largest integer that is less than or
+//                equal to 'x'.
+//    On Failure: None
+//
+LIBPBD_API float PBD_APICALLTYPE
+roundf(float x)
+{
+	return (floorf(x));
+}
+
 //***************************************************************
 //
 //	round()