Serialized diagnostics: encode a 24 bit version number as part of the "magic number" of serialized diagnostics.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143760 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/SerializedDiagnosticPrinter.cpp b/lib/Frontend/SerializedDiagnosticPrinter.cpp
index f1b5b1c..3516ad2 100644
--- a/lib/Frontend/SerializedDiagnosticPrinter.cpp
+++ b/lib/Frontend/SerializedDiagnosticPrinter.cpp
@@ -200,10 +200,8 @@
   
   // Emit the file header.
   Stream.Emit((unsigned)'D', 8);
-  Stream.Emit((unsigned)'I', 8);
-  Stream.Emit((unsigned)'A', 8);
-  Stream.Emit((unsigned)'G', 8);
-  
+  Stream.Emit((unsigned) Version, 32 - 8);
+
   EmitBlockInfoBlock();
 }