Add 'sdk/' from commit '2e7561d74f75de05dd7fb362f203f600afb451d7'

git-subtree-dir: sdk
git-subtree-mainline: 17a972d46f
git-subtree-split: 2e7561d74f

sdk/stb_image.c

@@ -0,0 +1,13 @@
+/*
+ * stb_image.c — stb_image 实现 TU。仅解 PNG/JPEG/BMP（其余格式关闭以减体积）。
+ * self-contained：PNG 内建 zlib 解码，不依赖系统 libz/libpng。
+ */
+#define STB_IMAGE_IMPLEMENTATION
+#define STBI_NO_PSD
+#define STBI_NO_TGA
+#define STBI_NO_GIF
+#define STBI_NO_PIC
+#define STBI_NO_PNM
+#define STBI_NO_HDR
+#define STBI_FAILURE_USERMSG
+#include "stb_image.h"