add an experimental tag for Gc<T> due to cycles

This type isn't yet very useful since it only pretends cycles won't be
a problem. Anyone using it should be made aware that they're going to
leak.
Mark LineIterator as public so its docs get generated.
extra: Ignore time tests on android correctly
Flag failure functions as inline(never)

The failure functions are generic, meaning they're candidates for getting
inlined across crates. This has been happening, leading to monstrosities like
that found in #11549. I have verified that the codegen is *much* better now that
we're not inlining the failure path (the slow path).
libstd: Added more #[inline] annotations and replaced uses of `libc::abort` with the intrinsic.
auto merge of #11557 : brson/rust/anotherandroidfix, r=thestinger
Fix formatting in rust-guide document.
auto merge of #11556 : am0d/rust/docs, r=huonw
register snapshots
remove the concept of managed-unique from libstd

Closes #11545
auto merge of #11561 : eddyb/rust/moar-inlines, r=pcwalton
auto merge of #11564 : am0d/rust/dox, r=huonw

Needs a line break here for readability.
Add a configure to disable libstd version injection

We'll use this when building snapshots so we can upgrade freely, but all
compilers will inject a version by default.
Revert "show options for -W help and -W". Fixes #11458.

This reverts commit 1009c21ad7b1db366a5c600946652cc490598ec1.
auto merge of #11523 : alexcrichton/rust/stage3, r=brson

This should go back to the old behavior while preserving the snapshot ease.
Use the least significant beat to determine if int/uint is even
libsyntax: Remove the obsolete ability to parse from substrings.

This was used by the quasiquoter.
auto merge of #11543 : thestinger/rust/gc, r=cmr

This type isn't yet very useful since it only pretends cycles won't be
a problem. Anyone using it should be made aware that they're going to
leak.
Allow more "error" values in try_recv()

This should allow callers to know whether the channel was empty or disconnected
without having to block.

Closes #11087
auto merge of #11112 : alexcrichton/rust/issue-11087, r=brson

This should allow callers to know whether the channel was empty or disconnected
without having to block.

Closes #11087