stb_image: Fix calculation of old size in stbi_realloc()
diff --git a/common/stb_image.patch b/common/stb_image.patch
index 87f6f719..33171d06 100644
--- a/common/stb_image.patch
+++ b/common/stb_image.patch
@@ -35,7 +35,7 @@
+ void *STBI_REALLOC_buf = (x); \
+ size_t STBI_REALLOC_alloc_size = (y); \
+ void *STBI_REALLOC_new_buf = STBI_MALLOC(STBI_REALLOC_alloc_size); \
-+ size_t STBI_REALLOC_old_size = *(size_t *)((void *)STBI_REALLOC_buf - 16); \
++ size_t STBI_REALLOC_old_size = (*(size_t *)((void *)STBI_REALLOC_buf - 16)) - 16; \
+ if (STBI_REALLOC_buf != NULL) { \
+ memcpy(STBI_REALLOC_new_buf, STBI_REALLOC_buf, \
+ MIN(STBI_REALLOC_alloc_size, STBI_REALLOC_old_size)); \
