Remove Emscripten support

lib/Target/JSBackend/MCTargetDesc/JSBackendMCTargetDesc.h

Index: lib/Target/JSBackend/MCTargetDesc/JSBackendMCTargetDesc.h
diff --git a/lib/Target/JSBackend/MCTargetDesc/JSBackendMCTargetDesc.h b/lib/Target/JSBackend/MCTargetDesc/JSBackendMCTargetDesc.h
deleted file mode 100644
index c98a55df83ba58cfc76b4ef4b5391c3df38d00b2..0000000000000000000000000000000000000000
--- a/lib/Target/JSBackend/MCTargetDesc/JSBackendMCTargetDesc.h
+++ /dev/null
@@ -1,25 +0,0 @@
-//===- JSBackendMCTargetDesc.h - JS Backend Target Descriptions -*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file provides asm.js specific target descriptions.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef JSBACKENDMCTARGETDESC_H
-#define JSBACKENDMCTARGETDESC_H
-
-#include "llvm/Support/TargetRegistry.h"
-
-namespace llvm {
-
-extern Target TheJSBackendTarget;
-
-} // End llvm namespace
-
-#endif