report a bug in minesweeper

[Cao-Wuhui]

I noticed that there's a bug in usr/minesweeper.c.
The function mine_mark() is defined in line 304~311 to mark the mine if this cell is not opened.

// usr/minesweeper.c, line 304~311
void mine_mark(struct command *com){
  int x, y;
  x = com->x;
  y = com->y;

  if(!(board[x][y] & OPEN)) // check if the cell is opened
    board[x][y] ^= MARKED;
}

However the macro OPEN is not a status but a command.

// usr/minesweeper.c, line 15~28
// cell status
#define BOMB_MASK 15
#define OPENED 16
#define MARKED 32
#define BOMB   64

// command
#define INIT 0
#define IOPEN 1
#define OPEN 2
#define MARK 3
#define QUIT 4
#define HELP 5
#define NOP  6

So, in function mine_mark(), OPEN should be replaced with OPENED as follows:

void mine_mark(struct command *com){
  int x, y;
  x = com->x;
  y = com->y;

  if(!(board[x][y] & OPENED))
    board[x][y] ^= MARKED;
}

I'd say sorry that I am not familiar with github and my git skill is not good.
That is why I have to report in this way.