Represent 'unit' as C 'int'; change pattern match compilation to avoid 'goto'; change Postgres prepared statement compilation to make life easier for the GCC escape analysis; all this in support of better tail call optimization

table t : { X : int }

fun main () : transaction page =
    v <- query (SELECT * FROM t)
         (fn r (_ : int) => return (error <xml>Shot down!</xml>))
         0;
    return <xml>Result: {[v]}</xml>