Add (unsupported experimental) feature allowing byte aligned bitcode.

lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp

Index: lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
index fca2ee760e09af1c50b2356626c1931c8b8e191b..c4cae2ca8165aaa73ddcda0a9bbaaf6036e54ee3 100644
--- a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
@@ -1844,16 +1844,15 @@ std::error_code NaClBitcodeReader::InitStreamFromBuffer() {
     return Error(InvalidBitstream,
                  "Bitcode stream should be a multiple of 4 bytes in length");
 
-  const unsigned char *HeaderPtr = BufPtr;
-  if (Header.Read(HeaderPtr, BufEnd))
+  if (Header.Read(BufPtr, BufEnd))
     return Error(InvalidBitstream, Header.Unsupported());
 
-  StreamFile.reset(new NaClBitstreamReader(BufPtr, BufEnd,
-                                           Header.getHeaderSize()));
-  Stream.init(StreamFile.get());
-
   if (AcceptHeader())
     return Error(InvalidBitstream, Header.Unsupported());
+
+  StreamFile.reset(new NaClBitstreamReader(BufPtr, BufEnd, Header));
+  Stream.init(StreamFile.get());
+
   return std::error_code();
 }
 
@@ -1861,11 +1860,11 @@ std::error_code NaClBitcodeReader::InitLazyStream() {
   if (Header.Read(LazyStreamer))
     return Error(InvalidBitstream, Header.Unsupported());
 
-  StreamFile.reset(new NaClBitstreamReader(LazyStreamer,
-                                           Header.getHeaderSize()));
-  Stream.init(StreamFile.get());
   if (AcceptHeader())
     return Error(InvalidBitstream, Header.Unsupported());
+
+  StreamFile.reset(new NaClBitstreamReader(LazyStreamer, Header));
+  Stream.init(StreamFile.get());
   return std::error_code();
 }