Add a rustdoc test for default methods in external crates

Author: sanxiyn

src/test/run-make/rustdoc-extern-default-method/Makefile

@@ -0,0 +1,6 @@
+-include ../tools.mk
+
+all: lib.rs ext.rs
+	$(HOST_RPATH_ENV) $(RUSTC) ext.rs
+	$(HOST_RPATH_ENV) $(RUSTDOC) -L $(TMPDIR) -w html -o $(TMPDIR)/doc lib.rs
+	$(HTMLDOCCK) $(TMPDIR)/doc lib.rs

src/test/run-make/rustdoc-extern-default-method/ext.rs

@@ -0,0 +1,21 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_type="lib"]
+
+pub trait Trait {
+    fn provided(&self) {}
+}
+
+pub struct Struct;
+
+impl Trait for Struct {
+    fn provided(&self) {}
+}

src/test/run-make/rustdoc-extern-default-method/lib.rs

@@ -0,0 +1,14 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+extern crate ext;
+
+// @count lib/struct.Struct.html '//*[@id="method.provided"]' 1
+pub use ext::Struct;