Idea: cargo edit lib

[bltavares]

Hi there!

First of all: Thanks for the project. It is great!

I've been working on crossgen to get support to build cross platform libs using Travis and Appveyor.

Sadly, I've come to face an issue with cargo where it is not possible to override the lib type through the command line.

One of the ideas I had was to be able to execute cargo edit lib --crate-type=staticlib and let it modify the manifest right before building. This would be added to the scripts, and would allow specifying only a single type of crate per target, without producing the rlib artifacts as well.

This would be very useful for C libs, but also WASM, as it needs to output a small library and it can't have the optimizations passed in if the manifest still have the lib.crate-type not overriden. (See)

What would you think of having this on cargo-edit? Or would you rather have this as a separate project?