Fix rocketcolor signedness
Fix background color calculation
Fix string quoting
Fix socket types
Silence warning about potentially uninitialized structure members
Fix warning about ambigious if-else-s
Avoid warnings about unused labels

maybejoystick label defined but not used when built without MOUSE
noshm label defined but not used when built without MITSHM
Get rid of unused variables if building with both MOUSE and JOYSTICK
Add SDL support