diff --git a/src/boost_regex.hpp b/src/boost_regex.hpp
index ac5b5fbced..a08b52b5af 100644
--- a/src/boost_regex.hpp
+++ b/src/boost_regex.hpp
@@ -10,6 +10,7 @@
 #   define NOMINMAX
 #  endif
 #  include <Windows.h>
+#  undef BASETYPES
 # endif
 #endif