auto merge of #13315 : alexcrichton/rust/libc, r=alexcrichton,me

Rebasing of #12526 with a very obscure bug fixed on windows.

src/test/compile-fail/attrs-after-extern-mod.rs

@@ -12,7 +12,7 @@
 // statics cannot. This ensures that there's some form of error if this is
 // attempted.
 
-use std::libc;
+extern crate libc;
 
 extern {
     static mut rust_dbg_static_mut: libc::c_int;

src/test/compile-fail/lint-ctypes.rs

@@ -10,7 +10,7 @@
 
 #![deny(ctypes)]
 
-use std::libc;
+extern crate libc;
 
 extern {
     pub fn bare_type1(size: int); //~ ERROR: found rust type

src/test/compile-fail/lint-dead-code-3.rs

@@ -14,6 +14,8 @@
 
 #![crate_type="lib"]
 
+extern crate libc;
+
 struct Foo; //~ ERROR: code is never used
 impl Foo {
     fn foo(&self) { //~ ERROR: code is never used
@@ -46,7 +48,7 @@ pub fn pub_fn() {
 }
 
 mod blah {
-    use std::libc::size_t;
+    use libc::size_t;
     // not warned because it's used in the parameter of `free` and return of
     // `malloc` below, which are also used.
     enum c_void {}

src/test/compile-fail/non-copyable-void.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::libc;
+extern crate libc;
 
 fn main() {
     let x : *Vec<int> = &vec!(1,2,3);

src/test/compile-fail/static-mut-foreign-requires-unsafe.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::libc;
+extern crate libc;
 
 extern {
     static mut a: libc::c_int;

src/test/compile-fail/unsupported-cast.rs

@@ -10,7 +10,7 @@
 
 // error-pattern:unsupported cast
 
-use std::libc;
+extern crate libc;
 
 fn main() {
   println!("{:?}", 1.0 as *libc::FILE); // Can't cast float to foreign.