Rename deprecated EnumSet methods in unit tests.
As of 4.9.2, gcc started passing -fno-lto to collect2, or to ld if collect2 cannot be found.  The latter is the case for our bundles, because we don't include collect2.  Unfortunately, ld does not understand this option and errors out.
On the bright side, -fno-use-linker-plugin still works to suppress gcc's LTO, so we can drop -fno-lto.
Move gcc back to rustlib\<triple>\bin
Prefer bundled linker.
Include some of the more popular Windows import libs into the bundle.
Fix ICEs that involved quasi-quotation

* fixed get_tt for doc comments
* properly handle MatchNt in `quote`

Fixes #18763
Fixes #18775
Add Encodable and Decodable for VecMap
Use FnvHashMap instead of HashMap in rustc
Fix broken documentation link
Rogue 'panic' -> 'fail' in guide.

Should refer to handling panicking tasks like any other computation
that may _fail_, not any other computation that may _panic_.
Document ast::Ty_
Fix 'renamed lint' warnings
Implement collection views API for TrieMap.
auto merge of #18287 : michaelsproul/rust/triemap-collection-views, r=bstrie

I've implemented the new collection views API for TrieMap. I more or less followed the approach set out by @Gankro in BTreeMap, by using a `SearchStack`. There's quite a bit of unsafe code, but I've wrapped it safely where I think is appropriate. I've added tests to ensure everything works, and performance seems quite good.

```
test trie::bench_map::bench_find                           ... bench:     67879 ns/iter (+/- 4192)
test trie::bench_map::bench_find_entry                     ... bench:    186814 ns/iter (+/- 18748)
test trie::bench_map::bench_insert_large                   ... bench:    716612 ns/iter (+/- 160121)
test trie::bench_map::bench_insert_large_entry             ... bench:    851219 ns/iter (+/- 20331)
test trie::bench_map::bench_remove                         ... bench:    838856 ns/iter (+/- 27998)
test trie::bench_map::bench_remove_entry                   ... bench:    981711 ns/iter (+/- 53046)
```

Using an entry is slow compared to a plain find, but is only ~15% slower for inserts and removes, which is where this API is most useful. I'm tempted to remove the standalone `remove` function in favour of an entry-based approach (to cut down on complexity).

I've added some more comments to the general part of the code-base, which will hopefully help the next person looking over this. I moved the three key structures to the top of the file so that the nesting structure is clearly visible, and renamed `Child<T>` to `TrieNode<T>` and `TrieNode<T>` to `InternalNode<T>` to improve clarity. If these changes are creeping, I'm happy to revert them.

Let me know if my use of `fail!` is ok, I was a little unsure of how specific to be. Some of the data-structures have various invariants that shouldn't be broken, so using `fail!` seemed appropriate.

## Still to do

* Modernise iterators (make them double-ended).
* Make the keys generic, or rename this data-structure (see: https://github.com/rust-lang/rust/issues/14902).
* Possibly move this code out of libcollections. [Searching Github for TrieMap turns up very few real results.][triemap-search]

Related issues: https://github.com/rust-lang/rust/issues/18009 and https://github.com/rust-lang/rust/issues/17320

[triemap-search]: https://github.com/search?utf8=%E2%9C%93&q=TrieMap+language%3ARust&type=Code&ref=searchresults
Attempt to fix the problem with failing distcheck.
vim: move 'move' to rustStorage
note the intent of reforming task spawning
mk: Fix configuration of version commit information

Commit bec2ee77f78b4bb8a503101091272a634a273a1c started quoting paths
discovered as part of the `probe` function, which includes git.  The
`make` `wildcard` function appears to be incompatible with quoted
paths so this check in the makefile now fails. Employing `wildcard`
here appears to only re-verify that git actually exists, which the
configure script already did, so I've just removed it.

Additionally, with the quoted paths the `subst` function should no
longer be needed, so I've removed it as well.

Closes #18771
auto merge of #18857 : brson/rust/winescapefixes, r=alexcrichton
rustdoc: revise method counts in stability summary

Previously, the stability summary page attempted to associate impl
blocks with the module in which they were defined, rather than the
module defining the type they apply to (which is usually, but not
always, the same). Unfortunately, due to the basic architecture of
rustdoc, this meant that impls from re-exports were not being counted.

This commit makes the stability summary work the same way that rustdoc's
rendered output does: all methods are counted alongside the type they
apply to, no matter where the methods are defined.

In addition, for trait impl blocks only the stability of the overall
block is counted; the stability of the methods within is not
counted (since that stability level is part of the trait definition).

Fixes #18812