Migrate tcpdump to a dedicated user

[eadler]

Summary

"nobody" should only be used by NFS and nothing should run as
it. Instead give tcpdump a dedicated user.

(this was already approved by maintainer; phab is for mechanical
correctness)

[matthew]

This is good, but you need to add the last bit that will create the special user when the package is installed.

You shouldn't create the userid unconditionally for a package where the USER option defaults to off.

USER_VARS= USERS=${UNPRIV_USER} GROUPS=${UNPRIV_USER}

You should update the USER_DESC setting too

[eadler]

per @matthew

[matthew]

Test builds with the USER option selected are failing when trying to create the tcpdump group due to a malformed GIDs line.
Fixing that locally means everything builds OK, although there is this warning at the end of the configure phase:

...
configure: creating ./config.status
config.status: creating Makefile
config.status: creating tcpdump.1
config.status: creating config.h
config.status: executing default-1 commands
configure: WARNING: unrecognized options: --enable-ipv6

Looks like IPv6 support is no longer optional.

GIDs

828

You're missing a field here:

tcpdump:*:885

[matthew]

Approved, subject to addressing my latest comments.