Copy Bitwriter to generate PNaClBitwriter.

include/llvm/Bitcode/PNaCl/PNaClBitstreamWriter.h

Index: include/llvm/Bitcode/PNaCl/PNaClBitstreamWriter.h
diff --git a/include/llvm/Bitcode/BitstreamWriter.h b/include/llvm/Bitcode/PNaCl/PNaClBitstreamWriter.h
similarity index 98%
copy from include/llvm/Bitcode/BitstreamWriter.h
copy to include/llvm/Bitcode/PNaCl/PNaClBitstreamWriter.h
index 7b68f8761afac305852ffc93ebd45d9f3f03dc43..2d6c95eba7eec720cc869e2f0a59c3ea57c0cd6f 100644
--- a/include/llvm/Bitcode/BitstreamWriter.h
+++ b/include/llvm/Bitcode/PNaCl/PNaClBitstreamWriter.h
@@ -12,8 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_BITCODE_BITSTREAMWRITER_H
-#define LLVM_BITCODE_BITSTREAMWRITER_H
+#ifndef LLVM_BITCODE_PNACLBITSTREAMWRITER_H
+#define LLVM_BITCODE_PNACLBITSTREAMWRITER_H
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
@@ -22,7 +22,7 @@
 
 namespace llvm {
 
-class BitstreamWriter {
+class PNaClBitstreamWriter {
   SmallVectorImpl<char> &Out;
 
   /// CurBit - Always between 0 and 31 inclusive, specifies the next bit to use.
@@ -93,10 +93,10 @@ class BitstreamWriter {
   }
 
 public:
-  explicit BitstreamWriter(SmallVectorImpl<char> &O)
+  explicit PNaClBitstreamWriter(SmallVectorImpl<char> &O)
     : Out(O), CurBit(0), CurValue(0), CurCodeSize(2) {}
 
-  ~BitstreamWriter() {
+  ~PNaClBitstreamWriter() {
     assert(CurBit == 0 && "Unflused data remaining");
     assert(BlockScope.empty() && CurAbbrevs.empty() && "Block imbalance");