Make LLVMContext and LLVMContextImpl classes instead of structs.

llvm-svn: 78690
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.h b/llvm/lib/Bitcode/Reader/BitcodeReader.h
index a1f9113..bd04888 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.h
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.h
@@ -26,7 +26,7 @@
 
 namespace llvm {
   class MemoryBuffer;
-  struct LLVMContext;
+  class LLVMContext;
   
 //===----------------------------------------------------------------------===//
 //                          BitcodeReaderValueList Class