move library-specific diagnostic headers into library private dirs.  Reduce
redundant #includes.  Patch by Anders Johnsen!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63271 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 2bf9300..72715c9 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -26,7 +26,7 @@
 
 #include "clang/Lex/Lexer.h"
 #include "clang/Lex/Preprocessor.h"
-#include "clang/Basic/DiagnosticLex.h"
+#include "clang/Lex/LexDiagnostic.h"
 #include "clang/Basic/SourceManager.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/MemoryBuffer.h"