(_AC_PROG_CXX_EXIT_DECLARATION):
Remove `#include <stdlib.h>' from the list; we should never
make confdefs.h include <stdlib.h> or <cstdlib>, because the
resulting namespace pollution would cause other tests to fail.
Configure scripts run with some older versions of g++ and HP's
aCC would fail due to such an #include. Problems reported by
Matthew Mueller in <http://bugs.debian.org/120704> and by
Keith Bostic in
<http://mail.gnu.org/archive/html/autoconf/2003-05/msg00063.html>.
In the test, use the test declaration before including <stdlib.h>,
as that's closer to how it'll be used.