Merge pull request Tencent#1603 from piratf/cmakelist_upgrade

fix CMake policy CMP0048 warning Tencent#1154

Author: miloyip

CMakeLists.txt

@@ -9,13 +9,18 @@ endif()
 
 SET(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/CMakeModules)
 
-PROJECT(RapidJSON CXX)
-
 set(LIB_MAJOR_VERSION "1")
 set(LIB_MINOR_VERSION "1")
 set(LIB_PATCH_VERSION "0")
 set(LIB_VERSION_STRING "${LIB_MAJOR_VERSION}.${LIB_MINOR_VERSION}.${LIB_PATCH_VERSION}")
 
+if (CMAKE_VERSION VERSION_LESS 3.0)
+    PROJECT(RapidJSON CXX)
+else()
+    cmake_policy(SET CMP0048 NEW)
+    PROJECT(RapidJSON VERSION "${LIB_VERSION_STRING}" LANGUAGES CXX)
+endif()
+
 # compile in release with debug info mode by default
 if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING "Choose the type of build, options are: Debug Release RelWithDebInfo MinSizeRel." FORCE)