trying to fix symbol lookup error

spider_control/launch/spider_control.launch

spider_description/urdf/spider.gazebo

spider_description/urdf/spider.xacro

spider_gazebo/launch/spider_world.launch

spider_gazebo/package.xml

spider_gazebo/worlds/30.1.1.1282760.dem

spider_gazebo/worlds/Antactica.tif

spider_gazebo/worlds/Stone_Brushed_Khaki_.png

spider_gazebo/worlds/__Wood_Bamboo_Medium_1.png

spider_gazebo/worlds/a

spider_gazebo/worlds/an

spider_gazebo/worlds/an.aux.xml

spider_gazebo/worlds/ant

spider_gazebo/worlds/antarctica

spider_gazebo/worlds/dem

spider_gazebo/worlds/dem.aux.xml

spider_gazebo/worlds/spider.world