-Wall incorrectly complains about scanf with %a

["paul moore" <paulmoore100@xxxxxxxxxxx>]

gcc 3.3.1 (suse 9.0) & 3.2.2 (rh9)
 
#include <stdio.h>
void foo()
{
   char x;
   scanf("%a", &x);
}
 
compiled with -Wall incorrectly complains
"float format, pointer arg (arg2)"