syntax: Implement #![no_core]

This commit is an implementation of [RFC 1184][rfc] which tweaks the behavior of
the `#![no_std]` attribute and adds a new `#![no_core]` attribute. The
`#![no_std]` attribute now injects `extern crate core` at the top of the crate
as well as the libcore prelude into all modules (in the same manner as the
standard library's prelude). The `#![no_core]` attribute disables both std and
core injection.

[rfc]: https://github.com/rust-lang/rfcs/pull/1184

1 files changed, 8 insertions, 4 deletions

diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index f5f8508e9aa..4a4db61c3b9 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -98,7 +98,8 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::prelude::*;
+#[cfg(stage0)]
+use core::prelude::v1::*;
 
 use ascii::*;
 use borrow::{Borrow, IntoCow, ToOwned, Cow};
@@ -134,7 +135,8 @@ use self::platform::{is_sep_byte, is_verbatim_sep, MAIN_SEP_STR, parse_prefix};
 #[cfg(unix)]
 mod platform {
     use super::Prefix;
-    use core::prelude::*;
+    #[cfg(stage0)]
+    use core::prelude::v1::*;
     use ffi::OsStr;
 
     #[inline]
@@ -157,7 +159,8 @@ mod platform {
 
 #[cfg(windows)]
 mod platform {
-    use core::prelude::*;
+    #[cfg(stage0)]
+    use core::prelude::v1::*;
     use ascii::*;
 
     use super::{os_str_as_u8_slice, u8_slice_as_os_str, Prefix};
@@ -1747,7 +1750,8 @@ impl AsRef<Path> for PathBuf {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use core::prelude::*;
+    #[cfg(stage0)]
+    use core::prelude::v1::*;
     use string::{ToString, String};
     use vec::Vec;