mjpg-streamer在Ubuntu下编译成功，运行./start.sh可正常工作，但重新编译，使用U盘挂载到
开发板，在串口终端执行./start.sh时，出现如下错误，
即找不到共享文件
MJPG Streamer Version: svn rev: Unversioned directory
ERROR: could not find output plugin output_http.so
Perhaps you want to adjust the search path with:
# export LD_LIBRARY_PATH=/path/to/plugin/folder
dlopen: output_http.so: cannot open shared object file: No such file or directory
