add new options for the floppy probing into the grub shell. fix some bugs in the commands geometry and device.

stage2/shared.h

@@ -334,10 +334,17 @@ extern int use_curses;
 extern int verbose;
 /* The flag for read-only.  */
 extern int read_only;
+/* If this flag is true, assume that there is no floppy.  */
+extern int no_floppy;
+/* If this flag is true, probe the second floppy drive.  */
+extern int probe_second_floppy;
 /* The map between BIOS drives and UNIX device file names.  */
 extern char **device_map;
 /* The array of geometries.  */
 extern struct geometry *disks;
+/* Check if DEVICE can be read. If an error occurs, return zero,
+   otherwise return non-zero.  */
+extern int check_device (const char *device);
 /* Assign DRIVE to a device name DEVICE.  */
 extern void assign_device_name (int drive, const char *device);
 #endif