Fix crash when a program exits before it opens a window (STR #3484).

This crash and the fix are Windows specific.


git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@13007 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

CHANGES

@@ -137,6 +137,8 @@ Changes in FLTK 1.4.0					Released: ??? ?? 2017
   Bug Fixes
 
   - (add new items here)
+  - Fix a potential crash when a program exits before it opens a window
+    (Windows only, STR #3484).
   - Fix Fl_PNG_Image error handling. An error was potentially caused
     by error handling of the image library with setjmp/longjmp.
   - Fix Fl_Browser background and text color parsing (STR #3376).

src/Fl_win32.cxx

@@ -584,7 +584,7 @@ public:
     fl_free_fonts(); // do some Windows cleanup
     fl_cleanup_pens();
     OleUninitialize();
-    fl_brush_action(1);
+    if (fl_graphics_driver) fl_brush_action(1);
     fl_cleanup_dc_list();
     // This is actually too late in the cleanup process to remove the
     // clipboard notifications, but we have no earlier hook so we try