cmake install: failure on `nlohmann_json`

[tdegeus]

I am trying to install xtl using

mkdir build
cd build
cmake ..
make install

But cmake fails

CMake Warning at CMakeLists.txt:31 (find_package):
  By not providing "Findnlohmann_json.cmake" in CMAKE_MODULE_PATH this
  project has asked CMake to find a package configuration file provided by
  "nlohmann_json", but CMake did not find one.

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

    nlohmann_jsonConfig.cmake
    nlohmann_json-config.cmake

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

I don't think that there exits an official way to install this dependency. What is the proper way to proceed?

[JohanMabille]

nlohmann_json is an optional dependency, the cmake of the xtl has been fixed recently, see #90. I see three options here to fix the problem:

• you use the master branch
• you apply the change of #90 to your local CMakeLists.txt
• you install xtl from conda, you won't have any issue unless you try to use the json serialization. If you need it, you can install nlohmann_json from conda (it is available on the quantstack channel).