A lot of Ruby libraries just happen to use native extensions that rely on OS-packaged libraries being installed.

I'm surprised there isn't any part of the gem process that calls `pkg-config`, to verify if a gem will be able to install, given its native dependencies. Having `bundle install` bail out after just a second with "please install libfoo first" would be great, especially for CI.

> I've never had pip fail to install a dependency on me

`pip install` has never failed me, but `pip install --upgrade` fails for me quite a bit. Especially when I try to use it like `gem upgrade`, with a stanza like

    pip list --outdated --format=legacy | cut -d' ' -f1 | xargs pip install --upgrade