Unable to build snapd locally

The doc in the snapd repo seems to be outdated as it doesn’t build locally even after all the setups in multipass. https://github.com/snapcore/snapd/blob/master/HACKING.md

What I get when running the command snapcraft is

The 'build-aux/snap' directory is meant specifically for snapcraft, but it contains the following non-snapcraft-related paths, which is unsupported and will cause unexpected behavior:
- patches
- patches/apparmor
- patches/apparmor/parser-replace-dynamic_cast-with-is_type-method.patch

If you must store these files within the 'build-aux/snap' directory, move them to 'build-aux/snap/local', which is ignored by snapcraft.
Launching a VM.
error: cannot perform the following tasks:
- Mount snap "pc-kernel" (1469) (cannot refresh kernel with change created by old snapd that is missing gadget update task)
An error occurred when trying to execute "sudo -H env SNAPCRAFT_BUILD_ENVIRONMENT=managed-host HOME=/root SNAPCRAFT_HAS_TTY=True snap watch '--last=auto-refresh?'" with 'multipass': returned exit code 1.

Kindly help me with the procedure to build snapd locally

Try --destructive inside a Xenial VM with

snap install --channel=4.x/stable --classic snapcraft