message: Use PROJECT_SOURCE_DIR instead of CMAKE_SOURCE_DIR
  This is semantically more precise, and also enables ORCA to be included
  in other CMake projects
  [ci skip]
diff: # Copyright (c) 2015, Pivotal Software, Inc. All Rights Reserved.
  include_directories("${CMAKE_CURRENT_SOURCE_DIR}/include"
  - "${CMAKE_SOURCE_DIR}/libgpdbcost/include"
  - "${CMAKE_SOURCE_DIR}/libgpopt/include"
  - "${CMAKE_SOURCE_DIR}/libnaucrates/include")
  + "${PROJECT_SOURCE_DIR}/libgpdbcost/include"
  + "${PROJECT_SOURCE_DIR}/libgpopt/include"
  + "${PROJECT_SOURCE_DIR}/libnaucrates/include")
  # for the generated config.h file.
  include_directories(${PROJECT_BINARY_DIR}/libgpos/include/)
  