Add missing cctype includes.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161660 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/TokenConcatenation.cpp b/lib/Lex/TokenConcatenation.cpp
index 84a46ed..dd7ebb0 100644
--- a/lib/Lex/TokenConcatenation.cpp
+++ b/lib/Lex/TokenConcatenation.cpp
@@ -14,6 +14,7 @@
 #include "clang/Lex/TokenConcatenation.h"
 #include "clang/Lex/Preprocessor.h"
 #include "llvm/Support/ErrorHandling.h"
+#include <cctype>
 using namespace clang;