This is makes it easier to use these in simulation, plus it avoids
duplication. The only downside I see is that more UARTs get defined than
a board supports, but no existing code should break (no UARTs get
renamed for example).
In some cases, regular integers were used. But we have a constant to
explicitly say these pins are undefined: `NoPin`. So use this.
A better solution would be to not require these constants, like with the
proposal in https://github.com/tinygo-org/tinygo/issues/3152. This
change is just a slight improvement over the current state.
Ayke van Laethem
sago35
Yurii Soldak
Kenneth Bell
BCG