librustc: Always parse `macro!()`/`macro![]` as expressions if not
followed by a semicolon.

This allows code like `vec![1i, 2, 3].len();` to work.

This breaks code that uses macros as statements without putting
semicolons after them, such as:

    fn main() {
        ...
        assert!(a == b)
        assert!(c == d)
        println(...);
    }

It also breaks code that uses macros as items without semicolons:

    local_data_key!(foo)

    fn main() {
        println("hello world")
    }

Add semicolons to fix this code. Those two examples can be fixed as
follows:

    fn main() {
        ...
        assert!(a == b);
        assert!(c == d);
        println(...);
    }

    local_data_key!(foo);

    fn main() {
        println("hello world")
    }

RFC #378.

Closes #18635.

[breaking-change]
auto merge of #19984 : japaric/rust/macro-expressions, r=alexcrichton

followed by a semicolon.

This allows code like `vec![1i, 2, 3].len();` to work.

This breaks code that uses macros as statements without putting
semicolons after them, such as:

    fn main() {
        ...
        assert!(a == b)
        assert!(c == d)
        println(...);
    }

It also breaks code that uses macros as items without semicolons:

    local_data_key!(foo)

    fn main() {
        println("hello world")
    }

Add semicolons to fix this code. Those two examples can be fixed as
follows:

    fn main() {
        ...
        assert!(a == b);
        assert!(c == d);
        println(...);
    }

    local_data_key!(foo);

    fn main() {
        println("hello world")
    }

RFC #378.

Closes #18635.

[breaking-change]

---

Rebased version of #18958
r? @alexcrichton 
cc @pcwalton
Remove the guides.
makefile stuff

this is probably too simple, but it'll work for now
adding source text
Import
https://github.com/aturon/rust-book/commit/731f7bf7f8b9af5cbc580acf80156f33f5a99703
Build a local rustbook
Build to doc
pass make tidy
Better make-fu

Thanks @cmr! :heart
rust-book -> rustbook
address @brson comment here https://github.com/rust-lang/rust/pull/19897#issuecomment-67421749
Oops, renamed rustbook in the wrong place
some make work
Some changes per @alexcrichton
build infra works
Import Rustbook https://github.com/steveklabnik/rust-book/commit/f15e6e543b865bafa45c13b36ff47b10a7b7adbe
one more fix the build