Added SDL_RenderClear() as a fast method of clearing the screen to the drawing color. Renamed SDL_RenderPoint() and SDL_RenderLine() to SDL_RenderDrawPoint() and SDL_RenderDrawLine(). Added API for rectangle drawing (as opposed to filling) Added placeholder API functions for circles and ellipses ... I'm not sure whether these will stay. Optimized software line drawing quite a bit. Added support for Wu's anti-aliased line drawing, currently disabled by default.

define(AC_CHECK_DEFINE,[dnl
  AC_CACHE_CHECK(for $1 in $2, ac_cv_define_$1,
    AC_EGREP_CPP([YES_IS_DEFINED], [
#include <$2>
#ifdef $1
YES_IS_DEFINED
#endif
    ], ac_cv_define_$1=yes, ac_cv_define_$1=no)
  )
  if test "$ac_cv_define_$1" = "yes" ; then
    AC_DEFINE([HAVE_$1],[],[Added by AC_CHECK_DEFINE])
  fi
])dnl
AC_DEFINE([HAVE_$1],[],[Added by AC_CHECK_DEFINE])