AS_IF([test "x$have_terminal" != xyes -a "x$enable_terminal" = xyes],
[AC_MSG_ERROR([*** terminal support requested but required dependencies not available])],
[test "x$have_terminal" = xyes],
AS_IF([test "x$have_terminal" != xyes -a "x$enable_terminal" = xyes],
[AC_MSG_ERROR([*** terminal support requested but required dependencies not available])],
[test "x$have_terminal" = xyes],