安装Boost和Eigen3

稀里糊涂用了多年C++，至今不会装Boost 和Eigen3
今天尝试安装libpointmatcher
之前是用vcpkg装的boost，可能是因为没有添加环境变量，cmake-gui总是报错。
于是按照libpointmatcher的教程重新安装一遍Boost ：Installation of libpointmatcher on Windows using MSVC
这应该是我见过写得比较清晰明了的Boost 安装教程了。
包括后面的cmake-gui教程都很清晰明了。难得一见，故记录一下。

Install Boost

1. Download boost_<version>.zip

2. Extract boost_<version> in C:\dev

3. Go to your Boost source directory with your CLI, and do:

   .\bootstrap.bat
   .\b2.exe
   

4. Set the following three environment variables:
   BOOST_LIBRARYDIR = C:\dev\boost_<version>\stage\lib
BOOST_INCLUDEDIR = C:\dev\boost_<version>
BOOST_DIR = C:\dev\boost_<version>\stage\lib\cmake\Boost-<version>

5. Add C:\dev\boost_<version>\stage\lib to Path environment variable

Install Eigen3

Eigen is header only (see Eigen's "Getting stated" page) and don't need to be build.

1. Download eigen-<version>.zip
2. Extract eigen-<version> in C:\dev
3. Set EIGEN3_INC_DIR environment variable to C:\dev\eigen-<version> (folder with signature_of_eigen3_matrix_library file)