diff --git a/dtool/src/dtoolutil/pandaSystem.cxx b/dtool/src/dtoolutil/pandaSystem.cxx
index 3d80d0f6b5..667d08b8d9 100644
--- a/dtool/src/dtoolutil/pandaSystem.cxx
+++ b/dtool/src/dtoolutil/pandaSystem.cxx
@@ -61,6 +61,12 @@ PandaSystem() :
 #else
   set_system_tag("system", "malloc", "malloc");
 #endif
+
+#ifdef _LIBCPP_VERSION
+  set_system_tag("system", "stdlib", "libc++");
+#elif defined(__GLIBCXX__)
+  set_system_tag("system", "stdlib", "libstdc++");
+#endif
 }
 
 /**