Increasing the Watch Dog Timeout PIC 16F877A - CCS PIC C
You don't want that. Watchdog timers keep a close look on the correct operation of the microcontroller, and the controller should be able to reset the watchdog timer every so often, after a few tens of milliseconds maximum. For a modern microcontroller a period of 10 seconds is eternity; it may execute 100 million or more instructions in that time, in which anything can go wrong. Then you don't want to let it go for another 10 seconds before you take action. In that time a motor you should be controlling may burn.

If you can't spare 1 of those 100 million to reset the timer there's something seriously wrong with the structure of your code.