build error

[phpstatic]

../../module/nginx-video-thumbextractor-module/src/ngx_http_video_thumbextractor_module_utils.c:570:55: error: variable 'crop_ctx' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
        if (rc >= 0) rc = avfilter_link(scale_ctx, 0, crop_ctx, 0);
                                                      ^~~~~~~~
../../module/nginx-video-thumbextractor-module/src/ngx_http_video_thumbextractor_module_utils.c:433:30: note: initialize the variable 'crop_ctx' to silence this warning
    AVFilterContext *crop_ctx;
                             ^
                              = NULL
../../module/nginx-video-thumbextractor-module/src/ngx_http_video_thumbextractor_module_utils.c:558:47: error: variable 'transpose_ctx' may be uninitialized when used here
      [-Werror,-Wconditional-uninitialized]
        rc = avfilter_link(*buffersrc_ctx, 0, transpose_ctx, 0);
                                              ^~~~~~~~~~~~~
../../module/nginx-video-thumbextractor-module/src/ngx_http_video_thumbextractor_module_utils.c:430:35: note: initialize the variable 'transpose_ctx' to silence this warning
    AVFilterContext *transpose_ctx;
                                  ^
                                   = NULL
../../module/nginx-video-thumbextractor-module/src/ngx_http_video_thumbextractor_module_utils.c:560:63: error: variable 'transpose_cw_ctx' may be uninitialized when used here
      [-Werror,-Wconditional-uninitialized]
            if (rc >= 0) rc = avfilter_link(transpose_ctx, 0, transpose_cw_ctx, 0);
                                                              ^~~~~~~~~~~~~~~~
../../module/nginx-video-thumbextractor-module/src/ngx_http_video_thumbextractor_module_utils.c:431:38: note: initialize the variable 'transpose_cw_ctx' to silence this warning
    AVFilterContext *transpose_cw_ctx;