2 files changed, 5 insertions, 0 deletions
diff --git a/src/drivers/Darwin/Fl_Darwin_System_Driver.H b/src/drivers/Darwin/Fl_Darwin_System_Driver.H
index 910270653..12148fb55 100644
--- a/src/drivers/Darwin/Fl_Darwin_System_Driver.H
+++ b/src/drivers/Darwin/Fl_Darwin_System_Driver.H
@@ -44,6 +44,7 @@
 class Fl_Darwin_System_Driver : public Fl_System_Driver
 {
 public:
+  Fl_Darwin_System_Driver();
   virtual int single_arg(const char *arg);
   virtual int arg_and_value(const char *name, const char *value);
   virtual int compose(int &del);
diff --git a/src/drivers/Darwin/Fl_Darwin_System_Driver.cxx b/src/drivers/Darwin/Fl_Darwin_System_Driver.cxx
index 1430be536..8fbdac6ca 100644
--- a/src/drivers/Darwin/Fl_Darwin_System_Driver.cxx
+++ b/src/drivers/Darwin/Fl_Darwin_System_Driver.cxx
@@ -45,6 +45,10 @@ Fl_System_Driver *Fl_System_Driver::driver() {
   return d;
 }
 
+Fl_Darwin_System_Driver::Fl_Darwin_System_Driver() {
+  if (fl_mac_os_version == 0) fl_mac_os_version = Fl_X::calc_mac_os_version();
+}
+
 int Fl_Darwin_System_Driver::single_arg(const char *arg) {
   // The Finder application in MacOS X passes the "-psn_N_NNNNN" option to all apps.
   return (strncmp(arg, "psn_", 4) == 0);