Package IDs can now refer to a subdirectory of a particular source
tree, and not just a top-level directory with a src/ directory as its
parent.
For example, referring to the package ID a/b/c/d , in workspace W,
if W/src/a is a package, will build the sources for the package in
a/b/c/d (and not other crates in W/src/a).
Closes#6408
Automate more tests described in the commands.txt file,
and add infrastructure for running them. Right now, tests shell
out to call rustpkg. This is not ideal.
This commit won't be quite as useful until I implement RUST_PATH and
until we change `extern mod` to take a general string instead of
an identifier (#5682 and #6407).
With that said, now if you're using rustpkg and a program contains:
extern mod foo;
rustpkg will attempt to search for `foo`, so that you don't have to
provide a -L directory explicitly. In addition, rustpkg will
actually try to build and install `foo`, unless it's already
installed (specifically, I tested that `extern mod extra;` would
not cause it to try to find source for `extra` and compile it
again).
This is as per #5681.
Incidentally, I changed some driver code to infer the link name
from the crate link_meta attributes. If that change isn't ok, say
something. Also, I changed the addl_lib_search_paths field in the
session options to be an @mut ~[Path] so that it can be modified
after expansion but before later phases.