Update for LLVM API change.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@78259 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGBlocks.h b/lib/CodeGen/CGBlocks.h
index 5a0af04..42c4f73 100644
--- a/lib/CodeGen/CGBlocks.h
+++ b/lib/CodeGen/CGBlocks.h
@@ -39,7 +39,7 @@
   class TargetData;
   class FunctionType;
   class Value;
-  class LLVMContext;
+  struct LLVMContext;
 }
 
 namespace clang {