diff --git a/mozilla/xpcom/tools/registry/regxpcom.cpp b/mozilla/xpcom/tools/registry/regxpcom.cpp
index 92c4129ac69..f32c1a6e4c8 100644
--- a/mozilla/xpcom/tools/registry/regxpcom.cpp
+++ b/mozilla/xpcom/tools/registry/regxpcom.cpp
@@ -21,6 +21,12 @@
  */
 
 #include <iostream.h>
+
+#ifdef XP_MAC
+#include "macstdlibextras.h"
+#endif
+
+
 #include "plstr.h"
 #include "prlink.h"
 #include "nsIComponentManager.h"
@@ -129,6 +135,12 @@ int main(int argc, char *argv[])
 {
     int ret = 0;
 
+#ifdef XP_MAC
+#if DEBUG
+    InitializeSIOUX(1);
+#endif
+#endif
+
     NS_InitXPCOM(NULL, NULL);
 
     /* With no arguments, RegFactory will autoregister */