Add support giflib 5.1

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

kernel/kls_gif/fmt_codec_gif.cpp

@@ -567,7 +567,13 @@ void fmt_codec::read_close()
     finfo.meta.clear();
     finfo.image.clear();
 
-    if(gif) DGifCloseFile(gif);
+    if(gif) {
+#if defined(GIFLIB_MAJOR) && (GIFLIB_MAJOR > 5 || (GIFLIB_MAJOR == 5 && GIFLIB_MINOR >= 1))
+	DGifCloseFile(gif, NULL);
+#else
+	DGifCloseFile(gif);
+#endif
+    }
 }
 
 #include "fmt_codec_cd_func.h"