Various makefile and installation things.

main() is now always in the program. Also added a
    macro that doesn't set main at all so that users
    can have their own.
  The isosurf sample doesn't work anymore.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@6459 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/opengl/isosurf/isosurf.cpp

@@ -330,12 +330,20 @@ void TestGLCanvas::OnPaint( wxPaintEvent& event )
     // OnPaint handlers must always create a wxPaintDC.
     wxPaintDC dc(this);
 
+#ifndef __WXMOTIF__
+    if (!GetContext()) return;
+#endif
+
     draw1();
     SwapBuffers();
 }
 
 void TestGLCanvas::OnSize(wxSizeEvent& event)
 {
+#ifndef __WXMOTIF__
+    if (!GetContext()) return;
+#endif
+
     SetCurrent();
     int width, height;
     GetClientSize(& width, & height);