Subzero: Refactor x86 register definitions to use the alias mechanism.

src/IceBrowserCompileServer.cpp

Index: src/IceBrowserCompileServer.cpp
diff --git a/src/IceBrowserCompileServer.cpp b/src/IceBrowserCompileServer.cpp
index 4d5705f02b5c3d76d6545c27a3aae7b8c6a06040..94b991ad5469556144f01b2130c0c8eec1071641 100644
--- a/src/IceBrowserCompileServer.cpp
+++ b/src/IceBrowserCompileServer.cpp
@@ -94,8 +94,8 @@ struct nacl_irt_pnacl_compile_funcs SubzeroCallbacks {
 std::unique_ptr<llvm::raw_fd_ostream> getOutputStream(int FD) {
   if (FD <= 0)
     llvm::report_fatal_error("Invalid output FD");
-  const bool CloseOnDtor = true;
-  const bool Unbuffered = false;
+  constexpr bool CloseOnDtor = true;
+  constexpr bool Unbuffered = false;
   return std::unique_ptr<llvm::raw_fd_ostream>(
       new llvm::raw_fd_ostream(FD, CloseOnDtor, Unbuffered));
 }