Added documentation on how to build a completely useless SDL library. :)

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401488

src/timer/dummy/SDL_systimer.c

@@ -21,6 +21,9 @@
 */
 #include "SDL_config.h"
 
+#include "SDL_timer.h"
+#include "../SDL_timer_c.h"
+
 void SDL_StartTicks(void)
 {
 }