simplify fwd

HDembinski · HDembinski · commit 3b2b5e33568a · 2018-08-24T10:56:04.000+02:00
diff --git a/include/boost/histogram/histogram_fwd.hpp b/include/boost/histogram/histogram_fwd.hpp
@@ -7,11 +7,9 @@
 #ifndef _BOOST_HISTOGRAM_HISTOGRAM_FWD_HPP_
 #define _BOOST_HISTOGRAM_HISTOGRAM_FWD_HPP_
 
-#include <boost/mp11.hpp>
-#include <memory>
-#include <tuple>
-#include <type_traits>
+#include <memory> // for std::allocator
 #include <vector>
+#include <string>
 
 namespace boost {
 namespace histogram {
