cpp-ipc: Fix builds on non-FreeBSD BSDs

cpp-ipc is explicitely only available on Windows, Linux, QNX, and FreeBSD. Trying to build dolphin on any another BSD such as OpenBSD or Haiku currently leads to failure because of this.

Source/Core/DolphinQt/Settings/GameCubePane.cpp

@@ -143,7 +143,7 @@ void GameCubePane::CreateWidgets()
            EXIDeviceType::EthernetXLink,
            EXIDeviceType::EthernetTapServer,
            EXIDeviceType::EthernetBuiltIn,
-#if !defined(__APPLE__)
+#ifdef HAVE_CPPIPC
            EXIDeviceType::EthernetIPC,
 #endif
            EXIDeviceType::ModemTapServer,