userland atomics

[jnemeth%victoria.tc.ca@localhost (John Nemeth)]

     Do we have any kind of atomic operations in userland?  I'm working
with Asterisk 1.6.0.1 on NetBSD 5.99.3.  Its configure script trys to
link this program (along with a lot of #define):

int
main ()
{
int foo1; int foo2 = __sync_fetch_and_add(&foo1, 1);
  ;
  return 0;
}

For some reason, the corfigure script believes that it is successful;
however, linking of Asterisk fails later due to a missing symbol.