fourcc: fix fallout from using ptr::P.

Author: eddyb

src/libfourcc/lib.rs

@@ -63,10 +63,9 @@ use syntax::ext::base::{ExtCtxt, MacExpr};
 use syntax::ext::build::AstBuilder;
 use syntax::parse::token;
 use syntax::parse::token::InternedString;
+use syntax::ptr::P;
 use rustc::plugin::Registry;
 
-use std::gc::Gc;
-
 #[plugin_registrar]
 pub fn plugin_registrar(reg: &mut Registry) {
     reg.register_macro("fourcc", expand_syntax_ext);
@@ -135,7 +134,7 @@ struct Ident {
 }
 
 fn parse_tts(cx: &ExtCtxt,
-             tts: &[ast::TokenTree]) -> (Gc<ast::Expr>, Option<Ident>) {
+             tts: &[ast::TokenTree]) -> (P<ast::Expr>, Option<Ident>) {
     let p = &mut cx.new_parser_from_tts(tts);
     let ex = p.parse_expr();
     let id = if p.token == token::EOF {
@@ -156,7 +155,7 @@ fn parse_tts(cx: &ExtCtxt,
 fn target_endian_little(cx: &ExtCtxt, sp: Span) -> bool {
     let meta = cx.meta_name_value(sp, InternedString::new("target_endian"),
         ast::LitStr(InternedString::new("little"), ast::CookedStr));
-    contains(cx.cfg().as_slice(), meta)
+    contains(cx.cfg().as_slice(), &*meta)
 }
 
 // FIXME (10872): This is required to prevent an LLVM assert on Windows