build error for aloam velodyne

[yogeshflux]

[ 63%] Building CXX object FAST_LIO_SLAM/SC-PGO/CMakeFiles/alaserPGO.dir/src/laserPosegraphOptimization.cpp.o
In file included from /usr/local/include/eigen3/Eigen/Eigenvalues:35,
from /usr/local/include/eigen3/Eigen/Dense:7,
from /home/yogeshkumargn/ROS_WORKSPACES/fastlio_slam/src/FAST_LIO_SLAM/SC-PGO/src/laserMapping.cpp:53:
/usr/local/include/eigen3/Eigen/src/misc/RealSvd2x2.h:19:6: error: redefinition of ‘template<class MatrixType, class RealScalar, class Index> void Eigen::internal::real_2x2_jacobi_svd(const MatrixType&, Index, Index, Eigen::JacobiRotation, Eigen::JacobiRotation)

[srinivasrama]

@yogeshflux Please check your eigen version is: 3.3.4

[yuanchihpeng]

I changed my Eigen version to 3.3.4 and still cannot build. My system is Ubuntu 20.04 with ROS Noetic