added cmake config version file for proper cmake delivery

Author: oleurodecision

CMakeLists.txt

@@ -168,9 +168,15 @@ if(JSONCPP_WITH_PKGCONFIG_SUPPORT)
 endif()
 
 if(JSONCPP_WITH_CMAKE_PACKAGE)
+        include (CMakePackageConfigHelpers)
         install(EXPORT jsoncpp
                 DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/jsoncpp
                 FILE        jsoncppConfig.cmake)
+        write_basic_package_version_file ("${CMAKE_CURRENT_BINARY_DIR}/jsoncppConfigVersion.cmake"
+                VERSION ${PROJECT_VERSION}
+                COMPATIBILITY SameMajorVersion)
+        install(FILES ${CMAKE_CURRENT_BINARY_DIR}/jsoncppConfigVersion.cmake
+                DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/jsoncpp)
 endif()
 
 if(JSONCPP_WITH_TESTS)