Merge pull request #1079 from captaincrutches/cmake-include-dir

Make RapidJSON_INCLUDE_DIR non-blank in Config.cmake

CMakeLists.txt

@@ -181,6 +181,8 @@ EXPORT( PACKAGE ${PROJECT_NAME} )
 # ... for the build tree
 SET( CONFIG_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 SET( CONFIG_DIR ${CMAKE_CURRENT_BINARY_DIR})
+SET( ${PROJECT_NAME}_INCLUDE_DIR "\${${PROJECT_NAME}_SOURCE_DIR}/include" )
+
 CONFIGURE_FILE( ${CMAKE_CURRENT_SOURCE_DIR}/${PROJECT_NAME}Config.cmake.in
     ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake @ONLY )
 CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/${PROJECT_NAME}ConfigVersion.cmake.in