Fix warning for Android NDK compiler: "function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]"

https://stackoverflow.com/questions/42125/warning-error-function-declaration-isnt-a-prototype
In C int foo() and int foo(void) are different functions. int foo() accepts an arbitrary number of arguments, while int foo(void) accepts 0 arguments. In C++ they mean the same thing.

test/testdrawchessboard.c

@@ -28,7 +28,7 @@ SDL_Renderer *renderer;
 SDL_Surface *surface;
 int done;
 
-void DrawChessBoard()
+void DrawChessBoard(void)
 {
     int row = 0, column = 0, x = 0;
     SDL_Rect rect, darea;
@@ -53,7 +53,7 @@ void DrawChessBoard()
     SDL_RenderPresent(renderer);
 }
 
-void loop()
+void loop(void)
 {
     SDL_Event e;
     while (SDL_PollEvent(&e)) {