message: Rename BuildTests to JSON_BuildTests
  This avoids potential conflicts with other libraries when the library is
  built from source and included in a bigger cmake build.
diff: @@ -5,7 +5,7 @@ project(nlohmann_json VERSION 2.1.1 LANGUAGES CXX)
  enable_testing()
  -option(BuildTests "Build the unit tests" ON)
  +option(JSON_BuildTests "Build the unit tests" ON)
  # define project variables
  set(JSON_TARGET_NAME ${PROJECT_NAME})
  @@ -25,7 +25,7 @@ target_include_directories(${JSON_TARGET_NAME} INTERFACE
  $<INSTALL_INTERFACE:${JSON_INCLUDE_DESTINATION}>)
  # create and configure the unit test target
  -if(BuildTests)
  +if(JSON_BuildTests)
  add_subdirectory(test)
  endif()
  