Revert "Remove wrong check for img_resample() when ffmpeg is built with...

Revert "Remove wrong check for img_resample() when ffmpeg is built with libswscale. img_resample() is on the list of deprecated functions and is currently mutual exclusive with swscale." It was the wrong fix.

This reverts commit e1629c21.

configure.ac

@@ -3028,7 +3028,10 @@ dnl Trying with pkg-config
        VLC_ADD_LIBS([ffmpeg],[${SWSCALE_LIBS}])
        AC_CHECK_LIB(swscale, sws_getContext,
          [AC_CHECK_HEADERS([ffmpeg/swscale.h libswscale/swscale.h])],
-         [],
+         [AC_CHECK_LIB(avcodec,img_resample,[],
+            [AC_MSG_ERROR([Your FFmpeg library doesn't have the needed img_resample() function. You should rebuild it with software scaler disabled, or install the swscale headers.])],
+         [${FFMPEG_LIBS}])
+         ],
          [${SWSCALE_LIBS}])
     ],[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, or install the swscale headers.])],