Add a copy-on-write container.
Added Freeze trait to CowArc
Allow SIMD types in generics. Closes #10604
Use an absolute path in test_process_output_fail_to_start

This test is designed to ensure that running a non-existent executable
results in a correct error message (FileNotFound in this case of this
test).  However, if you try to run an executable that doesn't exist, and
that requires searching through the $PATH, and one of the $PATH components
is not readable, then a PermissionDenied error will be returned, instead
of FileNotFound.
Unhide lines in rustdoc's doc -- Closes #11645
mk: remove -fno-omit-frame-pointer

This is still used for Rust code (`Options.NoFramePointerElim = true`).
Add a missing backslash to a makefile

Closes #11874
Fix a typo in disable rpaths

Closes #5219
Add test case for #3243, which was fixed as part of fix for #3511.
(Lifetime of stack allocated vectors was not being enforced)

Closes #3243.
Rename CopyableVector to CloneableVector
Rename OwnedCopyableVector to OwnedCloneableVector
Rename ImmutableCopyableVector to ImmutableCloneableVector
Rename CopyableTuple to CloneableTuple
Implement an unused_result lint

I attempted to implement the lint in two steps. My first attempt was a
default-warn lint about *all* unused results. While this attempt did indeed find
many possible bugs, I felt that the false-positive rate was too high to be
turned on by default for all of Rust.

My second attempt was to make unused-result a default-allow lint, but allow
certain types to opt-in to the notion of "you must use this". For example, the
Result type is now flagged with #[must_use]. This lint about "must use" types is
warn by default (it's different from unused-result).

The unused_must_use lint had a 100% hit rate in the compiler, but there's not
that many places that return Result right now. I believe that this lint is a
crucial step towards moving away from conditions for I/O (because all I/O will
return Result by default). I'm worried that this lint is a little too specific
to Result itself, but I believe that the false positive rate for the
unused_result lint is too high to make it useful when turned on by default.
extra: move arena to libarena

In line with the dissolution of libextra - #8784 - moves arena to its own library libarena.
Changes based on PR #11787. Updates .gitignore to ignore doc/arena.
auto merge of #11883 : alexcrichton/rust/fix-mk-install, r=pnkfelix

Closes #11874
Add a limited prim type lookup for safer const expr evaluation
auto merge of #11887 : alexcrichton/rust/rpath-for-real, r=thestinger

Closes #5219
extra: move glob to libglob

In line with the dissolution of libextra - moves glob to its own library libglob.
Changes based on PR #11787. Updates .gitignore to ignore doc/glob.
Generate rlibs by default (instead of dylibs)

Closes #11253