2.6.4 - let's try once more....

Because 2.6.2 couldn't be installed, the CI scripts couldn't run, and as a result 2.6.3 was bad because no testing had occurred on it.

This fixes a few (largely minor, aside from a widespread compile error) issues with 2.6.3, and also at the request of a user, adds support for configuring the watchdog timer to be forced on via the fuse (easy feature to add); though obviously I will note that unless you understand why you need the watchdog timer to keep the sketch from getting into a bad place, turning on the watchdog timer to force resets is the wrong approach. You should figure out what is going wrong, and then decide whether it is a bug you could fix, or is a condition forced on you by surrounding conditions, and hence . Note that this feature is only available for non-optiboot selections, because optiboot makes heavy use of the watchdog timer, and at best will have the wrong timeout, and at worst could fail entirely if the WDT is forced on.