Cargotest needs only one rustdoc.exe to exist on Windows

Author: Mark-Simulacrum

src/bootstrap/tool.rs

@@ -277,8 +277,11 @@ impl Step for Rustdoc {
 
         let mut cargo = prepare_tool_cargo(builder, build_compiler, target, "rustdoc");
         build.run(&mut cargo);
+        // Cargo adds a number of paths to the dylib search path on windows, which results in
+        // the wrong rustdoc being executed. To avoid the conflicting rustdocs, we name the "tool"
+        // rustdoc a different name.
         let tool_rustdoc = build.cargo_out(build_compiler, Mode::Tool, target)
-            .join(exe("rustdoc", &target_compiler.host));
+            .join(exe("rustdoc-tool-binary", &target_compiler.host));
 
         // don't create a stage0-sysroot/bin directory.
         if target_compiler.stage > 0 {

src/tools/rustdoc/Cargo.toml

@@ -3,8 +3,11 @@ name = "rustdoc-tool"
 version = "0.0.0"
 authors = ["The Rust Project Developers"]
 
+# Cargo adds a number of paths to the dylib search path on windows, which results in
+# the wrong rustdoc being executed. To avoid the conflicting rustdocs, we name the "tool"
+# rustdoc a different name.
 [[bin]]
-name = "rustdoc"
+name = "rustdoc-tool-binary"
 path = "main.rs"
 
 [dependencies]