shared/runtime/pyexec: Use MP_REGISTER_ROOT_POINTER().

This uses MP_REGISTER_ROOT_POINTER() to register repl_line
instead of using a conditional inside of mp_state_vm_t.

Signed-off-by: David Lechner <david@pybricks.com>

ports/minimal/Makefile

@@ -68,7 +68,7 @@ SRC_C += $(SRC_MOD)
 
 SRC_CXX += $(SRC_MOD_CXX)
 
-SRC_QSTR += shared/readline/readline.c
+SRC_QSTR += shared/readline/readline.c shared/runtime/pyexec.c
 SRC_QSTR += $(SRC_MOD) $(SRC_MOD_CXX)
 
 OBJ += $(PY_CORE_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))

ports/powerpc/Makefile

@@ -42,7 +42,7 @@ SRC_C = \
 	shared/runtime/stdout_helpers.c \
 	$(BUILD)/_frozen_mpy.c \
 
-SRC_QSTR += shared/readline/readline.c
+SRC_QSTR += shared/readline/readline.c shared/runtime/pyexec.c
 
 OBJ = $(PY_CORE_O)
 OBJ += $(addprefix $(BUILD)/, $(SRC_C:.c=.o))

py/mpstate.h

@@ -198,10 +198,6 @@ typedef struct _mp_state_vm_t {
 
     // root pointers for extmod
 
-    #if MICROPY_REPL_EVENT_DRIVEN
-    vstr_t *repl_line;
-    #endif
-
     #if MICROPY_PY_OS_DUPTERM
     mp_obj_t dupterm_objs[MICROPY_PY_OS_DUPTERM];
     #endif

shared/runtime/pyexec.c

@@ -488,6 +488,8 @@ int pyexec_event_repl_process_char(int c) {
     return res;
 }
 
+MP_REGISTER_ROOT_POINTER(vstr_t * repl_line);
+
 #else // MICROPY_REPL_EVENT_DRIVEN
 
 int pyexec_raw_repl(void) {