Bug#691349: "GNU Tools for ARM Embedded Processors"

[bnewbold@robocracy.org]

ARM's recent generic pre-built GNU toolchain for Cortex-M* and Cortex-R* 
processors, and the newlib-nano library, may make creation of an 
arm-none-eabi-gcc toolchain much easier.

I would be willing to take a whack at a "gcc-arm-embedded" package (along 
the lines of gcc-avr) if chrysn doesn't.

I'm one of the developers of libmaple (very similar to libopencm3); we 
probably won't try to package that library any time soon (not stable 
enough), but we would love see libopencm3 and all of it's (overlapping) 
dependencies packaged.