Some improvements to the Cargo compiler file.
Use rustc's errorformat and add option to specify permanent parameters.
Updates based on kballard's feedback.
Added check for absolute file path, removed hard tab, and added documentation for new option.
Fix `Vec::map_in_place` not doing what is written in the comment
Fix for issue #17574
Look for standard crates in LIBDIR provided by --libdir option,
not in hardcoded libdir path. If there was no LIBDIR provided
during configuration fallback to hardcoded paths.

Thanks to Jan Niklas Hasse for solution and to Alex Crichton for improvements.

Closes #11671
Conformed the 100 char limit and changed colon to semicolon
Register new snapshots
libs: stabilize most numerics after RFC changes

This commit adds stability markers for the APIs that have recently been
aligned with [numerics
reform](https://github.com/rust-lang/rfcs/pull/369). For APIs that were
changed as part of that reform, `#[unstable]` is used to reflect the
recency, but the APIs will become `#[stable]` in a follow-up pass.

In addition, a few aspects of the APIs not explicitly covered by the RFC
are marked here -- in particular, constants for floats.

This commit does not mark the `uint` or `int` modules as `#[stable]`,
given the ongoing debate out the names and roles of these types.

Due to some deprecation (see the RFC for details), this is a:

[breaking-change]
Fallout from deprecation
Adding switch in vim plugin to toggle format opts
Move closure checking into its own file. Shrink check/mod.rs!
Deduce the argument types based on the expected type, trawling through the fulfillment contect if necessary.
doc: clarifying unsafe code vs undefined behavior
Add myself as an author
Rename json::List to json::Array

Fixes #19010
auto merge of #19082 : alexcrichton/rust/snapshots, r=jakub-,jakub
Merge the ExprFnBlock and ExprUnboxedClosure into one ExprClosure with an optional unboxed closure kind.
Use the expected type to decide whether `||` is an unboxed or boxed closure.