gdb: info breakpoints显示所有断点

效果如下，

(gdb) info br
Num Type Disp Enb Address What
1 breakpoint keep y <PENDING> vtysh_init_vty
4 breakpoint keep y 0x00007ffff42bda0f in main at isis_main.c:348
breakpoint already hit 1 time
6 breakpoint keep y <MULTIPLE>
breakpoint already hit 3 times
6.1 y 0x00007ffff4303294 in zlog_set_level at log.c:664
6.2 y 0x00007ffff48e0b10 in zlog_set_level at log.c:664
7 breakpoint keep y <MULTIPLE>
7.1 y 0x00007ffff4301418 in vzlog at log.c:151
7.2 y 0x00007ffff48dec94 in vzlog at log.c:151