rustc: Remove f{32,64} % from the language

This commit removes the compiler support for floating point modulus operations,
as well as from the language. An implementation for this operator is now
required to be provided by libraries.

Floating point modulus is rarely used, doesn't exist in C, and is always lowered
to an fmod library call by LLVM, and LLVM is considering removing support
entirely.

Closes #12278
Remove redundant variable in LruCache::put
Eliminate unecessary extra sigil node from LruCache.

Instead of allocating both head and tail nodes for the ends of the node
list, a single node can be allocated and linked circularly instead,
making it act as both the head and the tail of the list at the same
time.
Use more precise span when reporting semicolon hint

When reporting "consider removing this semicolon" hint message, the
offending semicolon may come from macro call site instead of macro
itself. Using the more appropriate span makes the hint more helpful.

Closes #13428.
doc: add webfonts and tweak the styles accordingly
green: Fix missing Send bounds on procedures

These were mistakenly not updated as part of the removal of the Send bound by
default on procedures.

cc #13629
mk: Pass exact compile to rustc on cross compiles

Instead of passing through CC which may have things like ccache and other
arguments (when using clang) this commit filters out the necessary arguments
from CC to pass the right linker to rustc.

Closes #13562
Eliminate the need for Options in LruEntry.

LruEntry nodes previously used Option to encapsulate the key and value
fields. This was used merely as a way avoid having values for the sigil
node. Apart from wasting a few bytes for the discriminant, this
cluttered the rest of the code, since these fields always contained
Some on regular nodes as a class invariant.

The Option wrapping was removed, and the values in the sigil field are
initialized using mem::init, so that they don't contain any real data.
Refactor ty_vec represent &[T] as &([T])

Refactores all uses of ty_vec and associated things to remove the vstore abstraction (still used for strings, for now). Pointers to vectors are stored as ty_rptr or ty_uniq wrapped around a ty_vec. There are no user-facing changes. Existing behaviour is preserved by special-casing many instances of pointers containing vectors. Hopefully with DST most of these hacks will go away. For now it is useful to leave them hanging around rather than abstracting them into a method or something.

Closes #13554.
Fix spelling mistakes in documentation and code.
auto merge of #13640 : jbcrail/rust/spelling-updates, r=alexcrichton
Minor changes in std::mem

Fixed a typo in the documentation of std::mem, and refactored a function to use match instead of if.

Also added a FIXME to the benchmarks at the end of the file stating that they should be moved to another place, because they have nothing to do with `mem` (see https://github.com/mozilla/rust/issues/13642)
Added run_flags directive to `compiletest`

Now it is possible to specify run-flags in tests. For example, by using `run-flags: --bench` the Bencher is run.
doc: unifying with rustdoc

Conflicts:
	src/doc/rust.md
rustc: feature gates errors should use the new attribute syntax
auto merge of #13643 : aochagavia/rust/pr-2, r=alexcrichton

Fixed a typo in the documentation of std::mem, and refactored a function to use match instead of if.

Also added a FIXME to the benchmarks at the end of the file stating that they should be moved to another place, because they have nothing to do with `mem` (see https://github.com/mozilla/rust/issues/13642)
auto merge of #13410 : alexcrichton/rust/issue-12278, r=pcwalton

This commit removes the compiler support for floating point modulus operations,
as well as from the language. An implementation for this operator is now
required to be provided by libraries.

Floating point modulus is rarely used, doesn't exist in C, and is always lowered
to an fmod library call by LLVM, and LLVM is considering removing support
entirely.

Closes #12278
rustc: Improve errors on private static methods

This gives a better NOTE error message when a privacy error is encountered with
a static method. Previously no note was emitted (due to lack of support), but
now a note is emitted indicating that the struct/enum itself is private.

Closes #13641
rustdoc: Display tuple structs correctly

The fields of tuple structs recently gained the ability to have privacy
associated with them, but rustdoc was not updated accodingly. This moves the
struct field filtering to the rendering phase in order to preserve the ordering
of struct fields to allow tuple structs to have their private fields printed as
underscores.

Closes #13594
auto merge of #13636 : nick29581/rust/ty_vec, r=pcwalton

Refactors all uses of ty_vec and associated things to remove the vstore abstraction (still used for strings, for now). Pointers to vectors are stored as ty_rptr or ty_uniq wrapped around a ty_vec. There are no user-facing changes. Existing behaviour is preserved by special-casing many instances of pointers containing vectors. Hopefully with DST most of these hacks will go away. For now it is useful to leave them hanging around rather than abstracting them into a method or something.

Closes #13554.