Removed some compiler warnings about duplicated
#defines (isnan and RAD_TO_DEGREE etc). Fixed
some C++ errors (missing casts for void *), before
realising that wiiuse must be compiled in C mode anyway.
git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@12439 178a84e3-b1eb-0310-8ba1-8eac791a3b58