Add the Mach.replyPort() system call

HelloMach.java

@@ -15,7 +15,7 @@ private static final int MSGH_BITS(int remote, int local) {
 
     private static void hello(MachPort stdout) throws Exception {
         ByteBuffer msg = ByteBuffer.allocateDirect(1000);
-        MachPort reply = MachPort.allocate();
+        MachPort reply = Mach.replyPort();
 
         msg.order(ByteOrder.nativeOrder());
 

mach/Mach.c

@@ -2,6 +2,13 @@
 #include <mach-java.h>
 #include "Mach.h"
 
+JNIEXPORT jobject JNICALL
+Java_org_gnu_mach_Mach_replyPort (JNIEnv *env, jclass cls)
+{
+    /* FIXME: exception */
+    return mach_java_makeport(env, mach_reply_port());
+}
+
 JNIEXPORT jint JNICALL
 Java_org_gnu_mach_Mach_msg (JNIEnv *env, jclass cls, jobject msg, jint option,
         jobject rcvName, jlong timeout, jobject notify)

mach/Mach.java

@@ -1,6 +1,9 @@
 package org.gnu.mach;
 import java.nio.ByteBuffer;
 
+/**
+ * Mach system calls.
+ */
 public class Mach {
     public static final long MSG_TIMEOUT_NONE = 0;
 
@@ -29,6 +32,14 @@ public class Mach {
     public static final int RCV_INTERRUPT   = 0x00000400;
     public static final int RCV_LARGE       = 0x00000800;
 
+    /**
+     * Create a reply port.
+     *
+     * This is a wrapper around the mach_reply_port() system call, which
+     * creates a new MachPort object with the returned name.
+     */
+    public static native MachPort replyPort();
+
     /**
      * Native call to mach_msg().
      *