Fixed size_t warnings on 64-bit build

src/events/SDL_touch.c

@@ -100,7 +100,8 @@ int
 SDL_AddTouch(const SDL_Touch * touch, char *name)
 {
     SDL_Touch **touchPads;
-    int index,length;
+    int index;
+    size_t length;
 
     if (SDL_GetTouchIndexId(touch->id) != -1) {
         SDL_SetError("Touch ID already in use");

src/stdlib/SDL_string.c

@@ -408,7 +408,7 @@ size_t SDL_utf8strlcpy(char *dst, const char *src, size_t dst_bytes)
 {
     size_t src_bytes = SDL_strlen(src);
     size_t bytes = SDL_min(src_bytes, dst_bytes - 1);
-    int i = 0;
+    size_t i = 0;
     char trailing_bytes = 0;
     if (bytes)
     {