windows: Make keyboard_interrupt_obj available, it's standard feature.

unix/main.c

@@ -401,10 +401,8 @@ int main(int argc, char **argv) {
 
     mp_init();
 
-    #ifndef _WIN32
     // create keyboard interrupt object
     MP_STATE_VM(keyboard_interrupt_obj) = mp_obj_new_exception(&mp_type_KeyboardInterrupt);
-    #endif
 
     char *home = getenv("HOME");
     char *path = getenv("MICROPYPATH");

windows/mpconfigport.h

@@ -156,7 +156,8 @@ extern const struct _mp_obj_module_t mp_module_time;
 
 #if MICROPY_USE_READLINE == 1
 #define MICROPY_PORT_ROOT_POINTERS \
-    char *readline_hist[50];
+    char *readline_hist[50]; \
+    mp_obj_t keyboard_interrupt_obj;
 #endif
 
 #define MP_STATE_PORT               MP_STATE_VM