qga/commands-posix: Fix listing ifaces for Solaris

The code for guest-network-get-interfaces needs a couple of small
adjustments for Solaris:

- The results from SIOCGIFHWADDR are documented as being in ifr_addr,
  not ifr_hwaddr (ifr_hwaddr doesn't exist on Solaris).

- The implementation of guest_get_network_stats is Linux-specific, so
  hide it under #ifdef CONFIG_LINUX. On non-Linux, we just won't
  provide network interface stats.

Signed-off-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <20220426195526.7699-4-adeason@sinenomine.net>

qga/commands-posix.c

@@ -2767,6 +2767,7 @@ guest_find_interface(GuestNetworkInterfaceList *head,
 static int guest_get_network_stats(const char *name,
                        GuestNetworkInterfaceStat *stats)
 {
+#ifdef CONFIG_LINUX
     int name_len;
     char const *devinfo = "/proc/net/dev";
     FILE *fp;
@@ -2822,6 +2823,7 @@ static int guest_get_network_stats(const char *name,
     fclose(fp);
     g_free(line);
     g_debug("/proc/net/dev: Interface '%s' not found", name);
+#endif /* CONFIG_LINUX */
     return -1;
 }
 
@@ -2887,8 +2889,11 @@ GuestNetworkInterfaceList *qmp_guest_network_get_interfaces(Error **errp)
                 }
 
             } else {
+#ifdef CONFIG_SOLARIS
+                mac_addr = (unsigned char *) &ifr.ifr_addr.sa_data;
+#else
                 mac_addr = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
-
+#endif
                 info->hardware_address =
                     g_strdup_printf("%02x:%02x:%02x:%02x:%02x:%02x",
                                     (int) mac_addr[0], (int) mac_addr[1],