Upgrade Emscripten targets to use upstream LLVM backend

 - Refactors the Emscripten target spec to share code with other wasm
   targets.
 - Replaces the incorrect wasm32 C call ABI with the old asmjs
   version, which is correct for both wasm32 and JS.
 - Updates the varargs ABI used by Emscripten and deletes the old one.
 - Removes the obsolete wasm32-experimental-emscripten target.
 - Temporarily makes Emscripten targets use panic=abort by default
   because supporting unwinding will require an LLVM patch.

1 files changed, 2 insertions, 4 deletions

diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index b7ce9c7b397..673ce0053ca 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -1046,11 +1046,9 @@ impl Step for Compiletest {
 
         // Also provide `rust_test_helpers` for the host.
         builder.ensure(native::TestHelpers { target: compiler.host });
+        // As well as the target
+        builder.ensure(native::TestHelpers { target });
 
-        // wasm32 can't build the test helpers
-        if !target.contains("wasm32") {
-            builder.ensure(native::TestHelpers { target });
-        }
         builder.ensure(RemoteCopyLibs { compiler, target });
 
         let mut cmd = builder.tool_cmd(Tool::Compiletest);