Use correct OpenSSL thread safety macros on OS X (closes #209) Create an Autoconf test to determine if pthread_t is a pointer or scalar type, and use the appropriate CRYPTO_THREADID_set macro based on the result.

fun main () : transaction page =
    let
        val x = 1
        val y = "Hello"
        val z = 3.45
    in
        return <xml>{[x]}, {[y]}, {[z]}</xml>
    end