The only thing you can do is disable that perticular interrupt and enable it in main loop after assuring port pin 3.2 is high.

Remove these instructions from int0()
EA = 0;
...
EA = 1;

and simply add

EX0 = 0;

and add the following in your main loop which I cosider is in while(1)

if(P3_2 == 1)
EX0 = 1;

you may add a little bit of delay as follows

if(P3_2 == 1)
{
EX0 = 1;
for(x = 0; x<255;x++);
}

This is simply called key debouncing :)


Regards
Sarang