Github issue:
https://github.com/nlohmann/json/issues/2073
nlohmann::json documents 2 way of depending on it using CMake
1) Copy-paste the project/source into your own project.
2) Install nlohman::json and then use find_package.
(1) pollutes your git repository, (2) requires everyone to install the
dependencies themselves.
Since 2018, CMake provide some kind of 'package manager' features using
[FetchContent](https://cmake.org/cmake/help/v3.17/module/FetchContent.html)
It gives the following:
~~~cmake
include(FetchContent)
FetchContent_Declare(json
GIT_REPOSITORY https://github.com/nlohmann/json
GIT_TAG v3.7.3)
FetchContent_GetProperties(json)
if(NOT json_POPULATED)
FetchContent_Populate(json)
add_subdirectory( ${json_SOURCE_DIR} ${json_BINARY_DIR} EXCLUDE_FROM_ALL)
endif()
~~~
Then declares the dependency in the target using it:
~~~cmake
target_link_library(my_project PRIVATE nlohmann_json::nlohmann_json
~~~
This patch updates the documentation and provides tests.
I created a `nlohmann-json` package for `build2` (https://build2.org) that have been published on the central public repository https://cppget.org : https://cppget.org/nlohmann-json (at the moment you can see that there is only one version: 3.7.3).
The repository of the package code is there: https://github.com/build2-packaging/nlohmann-json and is owned by the build2 community now. (with build2 you can use either a repository like cppget.org or a git repository so both are useful to users for different use cases).
This patch just add the basic information as to how to use this library with build2.
Also call out to the guidelines for using pkg-config dependencies first,
and reference it for other build systems as well.
Although the possibility of installing with a pkg-config file is
somewhat hidden away in the meson docs, it's been deemed less invasive
due to not distracting away from cmake. So it will have to do.
