fix -Wshorten-64-to-32 warnings in android builds.

see: https://github.com/libsdl-org/SDL/pull/4195#issuecomment-901506386

src/render/SDL_render.c

@@ -3343,7 +3343,7 @@ SDL_RenderCopyExF(SDL_Renderer * renderer, SDL_Texture * texture,
 }
 
 
-#define SDL_OFFSETOF(_TYPE,_MEMBER)  ((size_t)&(((_TYPE*)0)->_MEMBER))
+#define SDL_OFFSETOF(_TYPE,_MEMBER)  ((intptr_t)&(((_TYPE*)0)->_MEMBER))
 int
 SDL_RenderGeometry(SDL_Renderer *renderer,
                                SDL_Texture *texture,

src/render/software/SDL_triangle.c

@@ -156,21 +156,21 @@ static void bounding_rect(const SDL_Point *a, const SDL_Point *b, const SDL_Poin
 
 /* Use 64 bits precision to prevent overflow when interpolating color / texture with wide triangles */
 #define TRIANGLE_GET_TEXTCOORD                                                                          \
-                    int srcx = ((Sint64)w0 * s2s0_x + (Sint64)w1 * s2s1_x + s2_x_area.x) / area;        \
-                    int srcy = ((Sint64)w0 * s2s0_y + (Sint64)w1 * s2s1_y + s2_x_area.y) / area;        \
+                    int srcx = (int)(((Sint64)w0 * s2s0_x + (Sint64)w1 * s2s1_x + s2_x_area.x) / area); \
+                    int srcy = (int)(((Sint64)w0 * s2s0_y + (Sint64)w1 * s2s1_y + s2_x_area.y) / area); \
 
 #define TRIANGLE_GET_MAPPED_COLOR                                                                       \
-                    int r = ((Sint64)w0 * c0.r + (Sint64)w1 * c1.r + (Sint64)w2 * c2.r) / area;         \
-                    int g = ((Sint64)w0 * c0.g + (Sint64)w1 * c1.g + (Sint64)w2 * c2.g) / area;         \
-                    int b = ((Sint64)w0 * c0.b + (Sint64)w1 * c1.b + (Sint64)w2 * c2.b) / area;         \
-                    int a = ((Sint64)w0 * c0.a + (Sint64)w1 * c1.a + (Sint64)w2 * c2.a) / area;         \
+                    int r = (int)(((Sint64)w0 * c0.r + (Sint64)w1 * c1.r + (Sint64)w2 * c2.r) / area);  \
+                    int g = (int)(((Sint64)w0 * c0.g + (Sint64)w1 * c1.g + (Sint64)w2 * c2.g) / area);  \
+                    int b = (int)(((Sint64)w0 * c0.b + (Sint64)w1 * c1.b + (Sint64)w2 * c2.b) / area);  \
+                    int a = (int)(((Sint64)w0 * c0.a + (Sint64)w1 * c1.a + (Sint64)w2 * c2.a) / area);  \
                     int color = SDL_MapRGBA(format, r, g, b, a);                                        \
 
 #define TRIANGLE_GET_COLOR                                                                              \
-                    int r = ((Sint64)w0 * c0.r + (Sint64)w1 * c1.r + (Sint64)w2 * c2.r) / area;         \
-                    int g = ((Sint64)w0 * c0.g + (Sint64)w1 * c1.g + (Sint64)w2 * c2.g) / area;         \
-                    int b = ((Sint64)w0 * c0.b + (Sint64)w1 * c1.b + (Sint64)w2 * c2.b) / area;         \
-                    int a = ((Sint64)w0 * c0.a + (Sint64)w1 * c1.a + (Sint64)w2 * c2.a) / area;         \
+                    int r = (int)(((Sint64)w0 * c0.r + (Sint64)w1 * c1.r + (Sint64)w2 * c2.r) / area);  \
+                    int g = (int)(((Sint64)w0 * c0.g + (Sint64)w1 * c1.g + (Sint64)w2 * c2.g) / area);  \
+                    int b = (int)(((Sint64)w0 * c0.b + (Sint64)w1 * c1.b + (Sint64)w2 * c2.b) / area);  \
+                    int a = (int)(((Sint64)w0 * c0.a + (Sint64)w1 * c1.a + (Sint64)w2 * c2.a) / area);  \
 
 
 #define TRIANGLE_END_LOOP                                                                               \