auto merge of #13440 : huonw/rust/strbuf, r=alexcrichton

libstd: Implement `StrBuf`, a new string buffer type like `Vec`, and port all code over to use it.

Rebased & tests-fixed version of https://github.com/mozilla/rust/pull/13269

diff --cc src/compiletest/runtest.rs
Simple merge

diff --cc src/libcollections/bitv.rs
Simple merge

diff --cc src/libcollections/hashmap.rs
Simple merge

diff --cc src/libgetopts/lib.rs
Simple merge

diff --cc src/libglob/lib.rs
Simple merge

diff --cc src/librustc/metadata/tydecode.rs
Simple merge

diff --cc src/librustc/middle/resolve.rs
Simple merge

diff --cc src/librustc/middle/trans/debuginfo.rs
Simple merge

diff --cc src/librustc/middle/typeck/infer/error_reporting.rs
Simple merge

diff --cc src/librustc/util/ppaux.rs
index e7b925197076aefb7cdb21916bea9228c29453bb,fec86b0bbe8e1a90ff86ecd38baa1c655693177a..0a9c6ee8e5c0fcda6cbe31eaa91d04529d4afe2a
--- 1/src/librustc/util/ppaux.rs
--- 2/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@@ -258,15 -259,15 +259,15 @@@ pub fn ty_to_str(cx: &ctxt, typ: t) -> 
                        sig: &ty::FnSig)
                        -> ~str {
          let mut s = if abi == abi::Rust {
-             ~""
+             StrBuf::new()
          } else {
-             format!("extern {} ", abi.to_str())
+             StrBuf::from_owned_str(format!("extern {} ", abi.to_str()))
          };
  
 -        match purity {
 -            ast::ImpureFn => {}
 +        match fn_style {
 +            ast::NormalFn => {}
              _ => {
 -                s.push_str(purity.to_str());
 +                s.push_str(fn_style.to_str());
                  s.push_char(' ');
              }
          };

diff --cc src/librustdoc/clean.rs
Simple merge

diff --cc src/librustdoc/html/format.rs
Simple merge

diff --cc src/librustdoc/html/render.rs
Simple merge

diff --cc src/librustdoc/markdown.rs
Simple merge

diff --cc src/libsyntax/ast_util.rs
Simple merge

diff --cc src/libsyntax/parse/parser.rs
Simple merge

diff --cc src/libsyntax/print/pprust.rs
Simple merge