qt: Add floppy support to media history manager

src/floppy/fdd.c

@@ -76,6 +76,7 @@ typedef struct {
 fdd_t fdd[FDD_NUM];
 
 char floppyfns[FDD_NUM][512];
+char *fdd_image_history[FDD_NUM][FLOPPY_IMAGE_HISTORY];
 
 pc_timer_t fdd_poll_time[FDD_NUM];