Perform full rectangle intersection for empty rects

If we don't do that, we leave the x and y values uninitialized.

Fixes https://github.com/libsdl-org/sdl12-compat/issues/365

(cherry picked from commit ffd0ca4391dc012d11d7cbe22279ecc25400621b)

src/video/SDL_rect_impl.h

@@ -48,8 +48,6 @@ bool SDL_HASINTERSECTION(const RECTTYPE *A, const RECTTYPE *B)
                SDL_RECT_CAN_OVERFLOW(B)) {
         SDL_SetError("Potential rect math overflow");
         return false;
-    } else if (SDL_RECTEMPTY(A) || SDL_RECTEMPTY(B)) {
-        return false; // Special cases for empty rects
     }
 
     // Horizontal intersection
@@ -100,10 +98,6 @@ bool SDL_INTERSECTRECT(const RECTTYPE *A, const RECTTYPE *B, RECTTYPE *result)
     } else if (!result) {
         SDL_InvalidParamError("result");
         return false;
-    } else if (SDL_RECTEMPTY(A) || SDL_RECTEMPTY(B)) { // Special cases for empty rects
-        result->w = 0;
-        result->h = 0;
-        return false;
     }
 
     // Horizontal intersection