"rustpkg build" should use installed dependencies

[kud1ing]

I have a project where pkg.rs contains #[pkg_dep(url = "git://github.com/linuxfood/rustsqlite")];.

rustpkg build has indeed compiled and installed it as ~/.rustpkg/lib/libsqlite-8bfaabce55432db9-0.1.dylib.

But rustpkg build terminates with error: can't find crate for sqlite`` though.

I'd expected rustpkg to work like Haskell's cabal where you could first "cabal install" a dependency and then "cabal build" where the dependency is used.

[graydon]

Yes. It's incomplete presently, but this should eventually work.

[kud1ing]

Referencing meta-ticket #5677

[catamorphism]

This should be working, but #5682 will make it more useful.