Copy Bitwriter to generate PNaClBitwriter.

include/llvm/Bitcode/NaCl/NaClReaderWriter.h

+//===-- llvm/Bitcode/NaCl/NaClReaderWriter.h - ------------------*- C++ -*-===//
+//      NaCl Bitcode reader/writer.
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header defines interfaces to read and write LLVM bitcode files/streams.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BITCODE_NACL_NACLREADERWRITER_H
+#define LLVM_BITCODE_NACL_NACLREADERWRITER_H
+
+namespace llvm {
+  class Module;
+  class raw_ostream;
+
+  /// NaClWriteBitcodeToFile - Write the specified module to the
+  /// specified raw output stream, using PNaCl wire format.  For
+  /// streams where it matters, the given stream should be in "binary"
+  /// mode.
+  void NaClWriteBitcodeToFile(const Module *M, raw_ostream &Out);
+
+} // end llvm namespace
+#endif