VDE networking support

Adds VDE (https://github.com/virtualsquare/vde-2) support to 86Box.
- Adds new networking type
- Modifies networking configuration dialog
- Adds CMake Presets to build and debug under MacOS

src/include/86box/network.h

@@ -51,6 +51,7 @@
 #define NET_TYPE_NONE  0 /* networking disabled */
 #define NET_TYPE_SLIRP 1 /* use the SLiRP port forwarder */
 #define NET_TYPE_PCAP  2 /* use the (Win)Pcap API */
+#define NET_TYPE_VDE   3 /* use the VDE plug API */
 
 #define NET_MAX_FRAME  1518
 /* Queue size must be a power of 2 */
@@ -123,6 +124,7 @@ typedef struct netdrv_t {
 
 extern const netdrv_t net_pcap_drv;
 extern const netdrv_t net_slirp_drv;
+extern const netdrv_t net_vde_drv;
 
 struct _netcard_t {
     const device_t *device;
@@ -147,15 +149,27 @@ typedef struct {
     char description[128];
 } netdev_t;
 
+typedef struct {
+    int has_slirp: 1;
+    int has_pcap: 1;
+    int has_vde:  1;
+} network_devmap_t;
+
+
+#define HAS_NOSLIRP_NET(x)  (x.has_pcap || x.has_vde)
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /* Global variables. */
 extern int      nic_do_log; /* config */
-extern int      network_ndev;
+extern network_devmap_t network_devmap;
+extern int      network_ndev;           // Number of pcap devices
+extern network_devmap_t network_devmap; // Bitmap of available network types
 extern netdev_t network_devs[NET_HOST_INTF_MAX];
 
+
 /* Function prototypes. */
 extern void       network_init(void);
 extern netcard_t *network_attach(void *card_drv, uint8_t *mac, NETRXCB rx, NETSETLINKSTATE set_link_state);
@@ -166,6 +180,8 @@ extern int        network_available(void);
 extern void       network_tx(netcard_t *card, uint8_t *, int);
 
 extern int net_pcap_prepare(netdev_t *);
+extern int net_vde_prepare(void);
+
 
 extern void            network_connect(int id, int connect);
 extern int             network_is_connected(int id);