extras: fix WEBP_SWAP_16BIT_CSP check
this is defined to 0 by dsp.h if it wasn't defined previously, since:
extras: add WebPUnmultiplyARGB() convenience function
@@ -58,7 +58,7 @@ int WebPImportRGB565(const uint8_t* rgb565, WebPPicture* pic) {
for (y = 0; y < pic->height; ++y) {
const int width = pic->width;
for (x = 0; x < width; ++x) {
-#ifdef WEBP_SWAP_16BIT_CSP
+#if defined(WEBP_SWAP_16BIT_CSP) && (WEBP_SWAP_16BIT_CSP == 1)
const uint32_t rg = rgb565[2 * x + 1];
const uint32_t gb = rgb565[2 * x + 0];
#else
@@ -91,7 +91,7 @@ int WebPImportRGB4444(const uint8_t* rgb4444, WebPPicture* pic) {
for (y = 0; y < pic->height; ++y) {
const int width = pic->width;
for (x = 0; x < width; ++x) {
-#ifdef WEBP_SWAP_16BIT_CSP
+#if defined(WEBP_SWAP_16BIT_CSP) && (WEBP_SWAP_16BIT_CSP == 1)
const uint32_t rg = rgb4444[2 * x + 1];
const uint32_t ba = rgb4444[2 * x + 0];
#else
