Test fixes and rebase conflicts, round 1

src/doc/trpl/lang-items.md

@@ -16,7 +16,7 @@ and one for deallocation. A freestanding program that uses the `Box`
 sugar for dynamic allocations via `malloc` and `free`:
 
 ```
-#![feature(lang_items, box_syntax, start, no_std)]
+#![feature(lang_items, box_syntax, start, no_std, libc)]
 #![no_std]
 
 extern crate libc;

src/doc/trpl/no-stdlib.md

@@ -21,7 +21,7 @@ The function marked `#[start]` is passed the command line parameters
 in the same format as C:
 
 ```
-#![feature(lang_items, start, no_std)]
+#![feature(lang_items, start, no_std, libc)]
 #![no_std]
 
 // Pull in the system libc library for what crt0.o likely requires
@@ -104,7 +104,7 @@ As an example, here is a program that will calculate the dot product of two
 vectors provided from C, using idiomatic Rust practices.
 
 ```
-#![feature(lang_items, start, no_std)]
+#![feature(lang_items, start, no_std, core, libc)]
 #![no_std]
 
 # extern crate libc;

src/doc/trpl/tracing-macros.md

@@ -31,7 +31,7 @@ macro_rules! bct {
 
 This is pretty complex! we can see the output
 
- ```rust
+```rust,ignore
 #![feature(trace_macros)]
 
 macro_rules! bct {
@@ -61,6 +61,7 @@ fn main() {
 
     bct!(0, 0, 1, 1, 1 ; 1, 0, 1);
 }
+```
 
 This will print out a wall of text:
 

src/doc/trpl/unstable.md

@@ -0,0 +1 @@
+% Unstable Rust