Fixed signed/unsigned warning
diff --git a/src/video/SDL_bmp.c b/src/video/SDL_bmp.c
index f471341..c8f1a16 100644
--- a/src/video/SDL_bmp.c
+++ b/src/video/SDL_bmp.c
@@ -150,7 +150,7 @@ SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
biBitCount = SDL_ReadLE16(src);
biCompression = BI_RGB;
} else {
- const int headerSize = 40;
+ const unsigned int headerSize = 40;
biWidth = SDL_ReadLE32(src);
biHeight = SDL_ReadLE32(src);