mtr should be installed setuid so it doesn't require sudo

[dwt]

Please note we will close your issue without comment if you delete, do not read or do not fill out the issue checklist below and provide ALL the requested information. If you repeatedly fail to use the issue template, we will block you from ever submitting issues to Homebrew again.

• are reporting a bug others will be able to reproduce and not asking a question. If you're not sure or want to ask a question do so on our Discourse: https://discourse.brew.sh
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To help us debug your issue please explain:

• What you were trying to do (and why)

Trying to use mtr without sudo

• What happened (include command output)

% mtr 1.1 
Failure to open IPv4 sockets: Operation not permitted
Failure to open IPv6 sockets: Operation not permitted
mtr: Failure to start mtr-packet: Invalid argument

• What you expected to happen

mtr should just work

• Step-by-step reproduction instructions (by running brew install commands)

% brew install mtr
% mtr 1.1 

This was already discussed here but then just closed on moving repos. Basically on all linux distros mtr is installed as setuid root, and I am arguing (as did the people in Homebrew/legacy-homebrew#166) that this should also be the default for home-brew. If you disagree, please at least consider adding this as an option to the formula.

[fxcoudert]

This has been declined multiple times already: Homebrew's policy is to not install setuid binaries. See #14428 Homebrew/legacy-homebrew#50207 Homebrew/legacy-homebrew#43862 Homebrew/legacy-homebrew#40992