#include "support/strfwd.h"
+// Forward definitions do not work with libc++
+// but ios_base has already been defined in strfwd
+// if compiling with it
+#ifndef _LIBCPP_VERSION
namespace std {
class ios_base;
typedef basic_streambuf<char, char_traits<char> > streambuf;
}
+#endif
namespace lyx {