Removing extraneous file - I still needed that!

[TanninOne]

Node.js version: tested 7.7.4 and 9.4.0
Yarn version: tested 1.0.1 and 1.3.2

** Feature request **

I'm requesting a feature to completely disable the automatic removal of extraneous files that happens as part of other commands (yarn install --check-files in my case).

** Current behavior **

In my use case I run electron-rebuild to rebuild native modules for my version of electron.
From time to time I have to force yarn to reinstall some module so I remove it and run "yarn install --check-files" but every time I do that it goes and removes the build artifacts from all modules.

** Requested behavior **
I don't care for some extraneous files in my development environment. I'd much rather have some harmless files lying around than having to rebuild all native modules multiple times a day.

Obviously it would be nice if yarn only removed files I actually don't need anymore but I somehow doubt this will ever be possible so this shouldn't be part of some other command.
Yarn install --check-files is documented as "Verifies that already installed files in node_modules did not get removed." which is incorrect, the current behaviour is "Verifies that already installed files in node_modules did not get removed and removes files that were added post-install."
Ideally this would be two commands, maybe something like "yarn prune"? But obviously this would be a change of the interface so I'm just asking for a toggle to control the behavior.

[SudoNova]

Hello. It's been a while, I just wanted to bump this issue to know what is the status. Using shared node_modules for different subparts of a project can save resources, but yarn install always removes extraneous files. It would be nice if there was a switch for this, like --skip-cleanup.