XBT_PRIVATE std::string instr_pid(simgrid::s4u::Actor const& proc);
-extern XBT_PRIVATE std::set<std::string> created_categories;
-extern XBT_PRIVATE std::set<std::string> declared_marks;
-extern XBT_PRIVATE std::set<std::string> user_host_variables;
-extern XBT_PRIVATE std::set<std::string> user_vm_variables;
-extern XBT_PRIVATE std::set<std::string> user_link_variables;
+extern XBT_PRIVATE std::set<std::string, std::less<>> created_categories;
+extern XBT_PRIVATE std::set<std::string, std::less<>> declared_marks;
+extern XBT_PRIVATE std::set<std::string, std::less<>> user_host_variables;
+extern XBT_PRIVATE std::set<std::string, std::less<>> user_vm_variables;
+extern XBT_PRIVATE std::set<std::string, std::less<>> user_link_variables;
/* from instr_config.c */
XBT_PRIVATE bool TRACE_needs_platform();