use the gp_system_*dir functions instead of readdir/opendir/closedir
use the gp_system_*dir functions instead of readdir/opendir/closedir

for https://github.com/gphoto/libgphoto2/issues/33

gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2