In file included from ../libavutil/common.h:62,
                 from ../libavutil/avutil.h:41,
                 from swscale.h:31,
                 from rgb2rgb.c:32:
../libavutil/internal.h:296: error: static declaration of 'round' follows non-static declaration
../libavutil/internal.h:303: error: static declaration of 'roundf' follows non-static declaration