Rustpkg schedule

"Ready for use" as per metabug:

## Due September 30

• 7075: rustpkg should use workcache
• 6408: Package IDs pointing into a subdirectory
• 8524: recursive dependencies
• 7402: Installing to RUST_PATH
• 8405: Semantic versions
• 7240: Multi-crate packages

Port Servo to rustpkg (concurrently with the following)

Milestone 1: well-defined

Due October 15

• 7447: Possible refinements to version handling
• 6746: Module file names should be resolved relatively to the referring module
• 6365: rustpkg usage messages need work

Milestone 2: backwards-compatible

Due October 25

• 8523: RFC: remove linkage attributes
• 6480: rustpkg should make locally cached files read-only

Milestone 3: feature-complete

Due December 16

• 8673: Specifying a revision in an extern mod directive can lead to duplication
• 8672: rustpkg should put build output in a target-specific subdirectory
• 8522: rustpkg should accept command line flags for rustc
• 8520: Let rustpkg find sources in the current working directory even if it's not a workspace
• 8405: rustpkg should support semantic versions
• 7401: Expand the set of commands that a package script can implement
• 7242: Finish implementing all rustpkg commands
• 6409: In rustpkg, expose the ability to clone a git repository
• 6403: Teaching rustpkg how to build C libraries
• 5012: rustpkg's -c does not work.
• 2219: --attr flag

Milestone 4: self-hosting

Due January 15

• 5363: Build all rust libraries and binaries with rustpkg
• 4019: Rewrite tests.mk in Rust

Milestone 5: production-ready

Due February 7

• 8711: When searching the RUST_PATH, rustpkg ignores versions
• 8690: rustpkg test package_script_with_default_build makes bogus assumptions about the build directory layout
• 7879: rustpkg endlessly compiles dependencies
• 5219: Make rpath usage optional
• 3346: crate name in log map is taken from name of output binary, not the crate name

Milestone 6: far-future (everything else)

• 7243: Teach rustpkg how to unpack tarball packages and fetch via curl
• 6481: Add a lint command to rustpkg
• 6410: Write libgit2 bindings for Rust
• 6404: Teach rustpkg how to probe for C libraries and header files
• 6005: Rustpkg should know about docs
• 2805: Bindgen-based build tool that creates self-contained hybrid crates from foreign libraries
• 2124: Add a bindgen pass
• 1642: Continuous documentation server for rustpkg packages
• 1609: move rustpkg to its own repository
• 1453: Create a continuous integration server for building rustpkg packages