Ubuntu16.04 ：not providing "FindEigen3.cmake" in CMAKE_MODULE_PATH

下載了openpano源碼編譯過程中一直出錯，錯誤如下：

  CMake Error at src/CMakeLists.txt:15 (find_package):
  By not providing "FindEigen3.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Eigen3", but
  CMake did not find one.

  Could not find a package configuration file provided by "Eigen3" with any
  of the following names:

    Eigen3Config.cmake
    eigen3-config.cmake

  Add the installation prefix of "Eigen3" to CMAKE_PREFIX_PATH or set
  "Eigen3_DIR" to a directory containing one of the above files.  If "Eigen3"
  provides a separate development package or SDK, be sure it has 

下載eigen3即可。