Switch from GPLv2 to GPLv2+ Signed-off-by: Keith Packard <keithp@keithp.com>
altos: Add stack-guard code. Uses STM MPU to trap stack overflow. This marks the lowest portion of the stack as inaccessible to the CPU, causing the processor to fault when it reaches it. The fault then generates a panic message so that the user can know what happened. Signed-off-by: Keith Packard <keithp@keithp.com>