Add initial support for *-*-nacl target.

lib/Support/Triple.cpp

 //===--- Triple.cpp - Target triple helper class --------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/Triple.h"
@@ skipping 92 matching lines @@
   case MacOSX: return "macosx";
   case MinGW32: return "mingw32";
   case NetBSD: return "netbsd";
   case OpenBSD: return "openbsd";
   case Psp: return "psp";
   case Solaris: return "solaris";
   case Win32: return "win32";
   case Haiku: return "haiku";
   case Minix: return "minix";
   case RTEMS: return "rtems";
+  case NativeClient: return "nacl";
   }
 
   return "<invalid>";
 }
 
 const char *Triple::getEnvironmentTypeName(EnvironmentType Kind) {
   switch (Kind) {
   case UnknownEnvironment: return "unknown";
   case GNU: return "gnu";
   case GNUEABI: return "gnueabi";
@@ skipping 509 matching lines @@
 }
 
 void Triple::setEnvironmentName(StringRef Str) {
   setTriple(getArchName() + "-" + getVendorName() + "-" + getOSName() +
             "-" + Str);
 }
 
 void Triple::setOSAndEnvironmentName(StringRef Str) {
   setTriple(getArchName() + "-" + getVendorName() + "-" + Str);
 }