Fix build error on VS2017

diff --git a/Src/pch.h b/Src/pch.h
index 44a249f..7cfb671 100644 (file)
--- a/Src/pch.h
+++ b/Src/pch.h
@@ -14,4 +14,5 @@
 #include <functional>\r
 #include <cassert>\r
 #include <ctime>\r
+#include <cctype>\r
 #include <boost/flyweight.hpp>\r