This uses MP_REGISTER_ROOT_POINTER() to register the readline_history root
pointer array used by shared/readline.c and removes the registration from
all mpconfigport.h files.
This also required adding a new MICROPY_READLINE_HISTORY_SIZE config option
since not all ports used the same sized array.
Signed-off-by: David Lechner <david@pybricks.com>
To simplify config, there's no need to specify MP_PLAT_PRINT_STRN if it's
the same as the default definition in py/mpconfig.h.
Signed-off-by: Damien George <damien@micropython.org>
Note: the uncrustify configuration is explicitly set to 'add' instead of
'force' in order not to alter the comments which use extra spaces after //
as a means of indenting text for clarity.