Report a build issue

[Duan, Zhenzhong]

Hi,

When -Dlibnl=disabled, build failed as below:

../src/util/virnetdevbridge.c: In function 'virNetDevBridgeSetupVlans':
../src/util/virnetdevbridge.c:326:9: error: implicit declaration of function 
'virNetlinkBridgeVlanFilterSet'; did you mean 
'virNetDevBridgeGetVlanFiltering'? [-Werror=implicit-function-declaration]
  326 |     if (virNetlinkBridgeVlanFilterSet(ifname, RTM_DELLINK, 0, 1, 
&error) < 0) {
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |         virNetDevBridgeGetVlanFiltering
../src/util/virnetdevbridge.c:326:9: error: nested extern declaration of 
'virNetlinkBridgeVlanFilterSet' [-Werror=nested-externs]
../src/util/virnetdevbridge.c:326:47: error: 'RTM_DELLINK' undeclared (first 
use in this function)
  326 |     if (virNetlinkBridgeVlanFilterSet(ifname, RTM_DELLINK, 0, 1, 
&error) < 0) {
      |                                               ^~~~~~~~~~~
../src/util/virnetdevbridge.c:326:47: note: each undeclared identifier is 
reported only once for each function it appears in
../src/util/virnetdevbridge.c:346:55: error: 'RTM_SETLINK' undeclared (first 
use in this function)
  346 |             if (virNetlinkBridgeVlanFilterSet(ifname, RTM_SETLINK, 
flags,
      |                                                       ^~~~~~~~~~~
cc1: all warnings being treated as errors

Thanks
Zhenzhong