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/Basic/IdentifierTable.cpp b/lib/Basic/IdentifierTable.cpp
index 92cc179..4869ae1 100644
--- a/lib/Basic/IdentifierTable.cpp
+++ b/lib/Basic/IdentifierTable.cpp
@@ -20,6 +20,7 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/ErrorHandling.h"
+#include <cctype>
 #include <cstdio>
 
 using namespace clang;