I observed freeglut in X11 mode to be very verbose in logging
mouse and window events, which seems useful for freeglut
troubleshooting, but not so valuable for applications that log
their own information.
This patch adds optional defines FREEGLUT_WARNINGS
an FREEGLUT_ERRORS which default to true, but can be
defined to false as desired. Perhaps worth noting that some
platforms such as Android and NaCL don't really support
stdout and stderr.
- Nigel Stewart