Merge pull request #17987 from leungbk/vim-patch-4402

vim-patch:8.2.{4639,4402}: missing parenthesis may cause unexpected problems

src/nvim/getchar.c

@@ -2571,7 +2571,7 @@ int inchar(char_u *buf, int maxlen, long wait_time)
     // Don't use buf[] here, closescript() may have freed typebuf.tb_buf[]
     // and buf may be pointing inside typebuf.tb_buf[].
     if (got_int) {
-#define DUM_LEN MAXMAPLEN * 3 + 3
+#define DUM_LEN (MAXMAPLEN * 3 + 3)
       char_u dum[DUM_LEN + 1];
 
       for (;;) {