Release 0.6 changes:

• made linking with libc the default, since it's the most commonly used mode.
• added glutSwapInterval for vsync control.
• added extension check function: glutExtensionSupported.
• added GL entry point loading function: glutGetProcAddress.
• fixed f-key handling, and missing keycode translations on windows.
• added GLUT_ACTIVE_SUPER modifier.
• made all modifier key events available through the special key callbacks.
• implemented glutWarpPointer.
• added spaceball support on windows.
• implemented bitmap font drawing.
• added global symbols for window-system objects: miniglut_dpy, and miniglut_win.
• added simple UNIX makefile, to build on systems without GNU make.
• added MSVC (nmake) makefile.
• miscellaneous bugfixes.
• added two more test programs: "keyboard" and "vsync".