Can not find IPOPT

[fuhang1987]

trafficstars

CMakeLists.txt:24: error: By not providing "FindIPOPT.cmake" in CMAKE_MODULE_PATH this project has asked CMake to find a package configuration file provided by "IPOPT", but CMake did not find one. Could not find a package configuration file provided by "IPOPT" with any of the following names: IPOPTConfig.cmake ipopt-config.cmake Add the installation prefix of "IPOPT" to CMAKE_PREFIX_PATH or set "IPOPT_DIR" to a directory containing one of the above files. If "IPOPT" provides a separate development package or SDK, be sure it has been installed.

[zerolover]

replace https://github.com/LiJiangnanBit/path_optimizer/blob/5490467cd88bcf3c86b5355d16e9f5107e26bc18/CMakeLists.txt#L20 with LIST(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)