Proposed commit message:
This adds devel/arduino-bsd-mk which installs a make(1) makefile (bsd.arduino.mk) that is used to build Arduino sketches from the command line. It is designed to be an FreeBSD-friendly alternative to the existing gmake based devel/arduino-mk port. It includes a man page and optionally installs an example sketch with an exmaple Makefile. Reviewed by: ? (mentor) Approved by: ? (mentor) Differential Revision: ?
Add a note saying that the spec requires the upper byte of the device_id be 0x22, but that most vendors don't honor that, so that's why we're not checking for it. That makes the 0x22 in the generic case a bit less magic.