virnetdevmacvlan: Provide stubs for macvlan related functions

In recent commit of 3d21ff72 the virNetDevMacVLanTapOpen() and
virNetDevMacVLanTapSetup() functions were exported in our private
symbols. But these functions live in an #ifdef so they need a
stub implementation.
Then in 1b46566e the virNetDevMacVLanIsMacvtap() function was
implemented but again, only for #idef and without stub.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/util/virnetdevmacvlan.c

@@ -1178,6 +1178,13 @@ int virNetDevMacVLanRestartWithVPortProfile(const char *cr_ifname,
 }
 
 #else /* ! WITH_MACVTAP */
+bool virNetDevMacVLanIsMacvtap(const char *ifname ATTRIBUTE_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("Cannot create macvlan devices on this platform"));
+    return false;
+}
+
 int virNetDevMacVLanCreate(const char *ifname ATTRIBUTE_UNUSED,
                            const char *type ATTRIBUTE_UNUSED,
                            const virMacAddr *macaddress ATTRIBUTE_UNUSED,
@@ -1197,6 +1204,26 @@ int virNetDevMacVLanDelete(const char *ifname ATTRIBUTE_UNUSED)
     return -1;
 }
 
+int
+virNetDevMacVLanTapOpen(const char *ifname ATTRIBUTE_UNUSED,
+                        int *tapfd ATTRIBUTE_UNUSED,
+                        size_t tapfdSize ATTRIBUTE_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("Cannot create macvlan devices on this platform"));
+    return -1;
+}
+
+int
+virNetDevMacVLanTapSetup(int *tapfd ATTRIBUTE_UNUSED,
+                         size_t tapfdSize ATTRIBUTE_UNUSED,
+                         bool vnet_hdr ATTRIBUTE_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("Cannot create macvlan devices on this platform"));
+    return -1;
+}
+
 int virNetDevMacVLanCreateWithVPortProfile(const char *ifname ATTRIBUTE_UNUSED,
                                            const virMacAddr *macaddress ATTRIBUTE_UNUSED,
                                            const char *linkdev ATTRIBUTE_UNUSED,