Errors out at configure if libavcodec doesnt include img_resample()

Refs #1594

configure.ac

@@ -2770,6 +2770,17 @@ dnl Trying with pkg-config
  fi 
 fi
 
+dnl Check if we have (required) img_resample() in libavcodec
+if test "${enable_ffmpeg}" != "no"
+then
+     VLC_SAVE_FLAGS
+     CFLAGS="${CFLAGS} ${CFLAGS_ffmpeg}"
+     LDFLAGS="${LDFLAGS} ${LDFLAGS_ffmpeg}"
+     AC_CHECK_LIB(avcodec, img_resample, ,
+       [AC_MSG_ERROR([Your FFmpeg library doesn't have the needed img_resample() function. You should rebuild it with software scaler disabled])], -lavutil)
+     VLC_RESTORE_FLAGS
+fi
+
 dnl
 dnl  ffmpegaltivec plugin
 dnl