Build: Specify architecture in Mac packages

Apparently the installer architecture defaults to x86-64 (probably
because our macOS builds are performed on an Intel-based Mac), which
caused the user to be prompted to install Rosetta when attempting to
install the TurboVNC package for Macs with Apple silicon CPUs.

Refer to #350

ChangeLog.md

@@ -8,6 +8,9 @@ followed by a left Alt key release, caused the keyboard focus to be redirected
 to the system menu, and subsequent keystrokes were consumed by the system menu
 until left Alt or Esc was pressed to dismiss the menu.
 
+2. Fixed an issue whereby Rosetta was required in order to install the
+TurboVNC package for Macs with Apple silicon CPUs.
+
 
 3.0.2
 =====

release/Distribution.xml.in

@@ -21,7 +21,7 @@
 		enable_localSystem="true"
 	/>
 	<installation-check script="installationCheck()" />
-	<options customize="never" />
+	<options customize="never" hostArchitectures="@CPU_TYPE@" />
 	<choices-outline>
 		<line choice="default">
 			<line choice="@PKGID@"/>