The first commit fixes warnings about `pub use` imports because it can't be known whether those are actually used or not.

The second commit fixes using `#[level(unused_imports)]` style control over the emission of warnings. Before it looked like it only worked as a command-line flag.

This pull request moves the logic from os::make_absolute() into the path module and fixes path joining for Windows.  It does this by adding an ``unsafe_join()`` function that implements the operating system's path joining semantics.

Additionally it also adds an ``is_restricted()`` method to the trait which will return true if the path points to a windows device file.

r? @graydon

Removed deprecated `str()` functions in int-template.rs and uint-template.rs

r? @brson

I also deleted a test that would be entirely useless without capture clauses.

Copy the keyword list from rust.vim, and add `self` so that it is highlighted
(being liberal with the correct categories).

I'm not quite willing to dive in to clean up the emacs code yet, but at least this gets a (more) modern syntax highlighting list.

Note on `struct_elt`: the comment is wrong, it actually dereferences the nth element of LLVM struct type if it is a pointer. That's why `T_ptr` is removed in `callee.rs`.

Patch for #4517

This works for fixed vectors, but I am unclear how slices should be printed, simply '&[...]'  or...

e.i. How should regions be printed?

Fix issue #3645

Closes #4738.

The `std::smallintmap` module doesn't use an implicit @ box so I just added that explicitly for now to make porting simple.

This reverts commit f63efdc2.

Copy the keyword list, and add `self` so that it is somewhat highlighted
(being liberal with the correct categories).

Fix issue #3645