warning against common symbols

["GNVS Sudhakar" <ssudhakar@xxxxxxxxxx>]

Hi,

How do I get a warning if I use any library function by mistake? For
example I should get a warning if I try to compile the following program
(tried -Wl,--warn-common option but it didn't work.):

/*openlog is a c library function*/
void openlog(void) 
{
	volatile int i=0;
	i++;
}
int main(void)
{
	openlog();
	return 0;
}

Thanks
Sudhakar