Set a specific feature during doc generation

[dflemstr]

Use case: if your library depends on some native library or otherwise does something funky during build, it won't be exposed on docs.rs.

The build could check for the presence of a docs feature in the Cargo.toml file, for example like this:

cargo read-manifest | rq 'select"$.features"|map(o)=>{_.keys(o)}|spread|some(x)=>{"docs"==x}'

(Shameless plug: rq)

Setting this docs feature would allow the library to "defuse" itself, by not running a build script or not trying to link a native library.

[onur]

This is a good idea but I was planning to add an option for extra-features and no-default-features. This is a most requested feature for docs.rs. See: #29

Checking docs feature can also be useful.