move misc/printk.h to sys/printk.h and
create a shim for backward-compatibility.
No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.
Related to #16539
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Add a sample that demonstrates a custom board definition. This proves
that BOARD_ROOT works and can be a useful reference when creating a
custom board definition.
Instead of spending time making up a board, the nrf52840_pca10056
board has been copied as-is. And the hello world sample has been used
as the basis for the application.
Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
