* gnu/packages/patches/lightdm-vnc-ipv6.patch: New patch file.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/display-managers.scm (lightdm): Apply it.
* gnu/tests/lightdm.scm (run-lightdm-test): Remove comment and expected fail
directive for the "can connect to TCP port 5900 on IPv6" test.
Suggested-by: Bruno Victal <mirai@makinata.eu>
