diff -r 499243eb04d1 -r a71599790f7a QTfrontend/ui/widget/feedbackdialog.cpp
--- a/QTfrontend/ui/widget/feedbackdialog.cpp	Sat Apr 20 20:39:37 2013 +0200
+++ b/QTfrontend/ui/widget/feedbackdialog.cpp	Sat Apr 20 20:48:33 2013 +0200
@@ -44,6 +44,9 @@
 
 #ifdef Q_WS_MAC
 #include <sys/sysctl.h>
+#ifndef _SC_NPROCESSORS_ONLN
+#define _SC_NPROCESSORS_ONLN 58
+#endif
 #endif
 
 #include <stdint.h>