add imports for tuple in CTagsEmitter.cpp

Author: jerryyiransun

llvm/utils/TableGen/CTagsEmitter.cpp

@@ -17,6 +17,7 @@
 #include "llvm/TableGen/Error.h"
 #include "llvm/TableGen/Record.h"
 #include "llvm/TableGen/TableGenBackend.h"
+#include <tuple>
 #include <vector>
 using namespace llvm;