An effective way to forward a clock out of a device for clocking devices external to the device, is to use an ODDR component. By tying one input High and the other Low, you can easily create a well controlled clock in terms of phase relationship and duty cycle. For example, by holding D1 to 0 and the D2 pin to 1, you can achieve a 180 degree phase shift. You can control stopping the clock by using the set/reset and clock enable. You can hold the clock at a certain polarity for sustained amounts of time.
Use an MMCM if you need further phase control for an external clock. You can use it with external feedback compensation. It also supports coarse or fine-grained, fixed, or variable phase compensation. This allows great control over clock phase and propagation times to other devices simplifying external timing requirements from the device.