digitalPinToInterrupt() missing about duo

[dspdon]

Looking at the current folder tree, it may be simple to add this macro to:
...\X_hal\inc\pinmap_hal.h
but it seems best to keep to the standard Arduino file hierarchy by adding a new "pins_arduino.h" file here:
...\STM32F2\0.2.6\variants\RedBear_Duo\pins_arduino.h

I'm seeing similar errors about missing definitions in the SPI interface (no BitOrder type, etc).

[dspdon]

I learned that the interrupts on Duo take a pin number, not interrupt number. Seems better overall, but this is compatible with some legacy code. Closing this issue.