Add suitable #include for HAVE_MC

diff --git a/include/xbt/string.hpp b/include/xbt/string.hpp
index 738cf32..9840855 100644 (file)
--- a/include/xbt/string.hpp
+++ b/include/xbt/string.hpp
@@ -7,6 +7,8 @@
 #ifndef SIMGRID_XBT_STRING_HPP
 #define SIMGRID_XBT_STRING_HPP
 
+#include <simgrid_config.h>
+
 #if HAVE_MC
 
 #include <stdexcept>