Description: Fix FTBFS on big endian architectures.
Bug: https://bugzilla.libsdl.org/show_bug.cgi?id=2063

--- a/IMG_webp.c
+++ b/IMG_webp.c
@@ -186,7 +186,7 @@ SDL_Surface *IMG_LoadWEBP_RW(SDL_RWops *src)
     WebPBitstreamFeatures features;
     int raw_data_size;
     uint8_t *raw_data = NULL;
-    int r;
+    int r, s;
     uint8_t *ret;
 
     if ( !src ) {