message: In order to use protobuf 3.0 on Mac, add variable MAC_PROTOBUF_VERSION.
  By default, it's still built against version 2.5.0.
diff: @@ -206,9 +206,13 @@ macro(config_protobuf)
  set(PROTOBUF_LIBRARIES_DIRECTORY ${THIRDPARTY_LIB_ROOT}/protobuf/protobuf-3.0/vc${VS_VERSION}-${ARCH}/lib)
  set(PROTOBUF_FOUND ON)
  elseif(CMAKE_HOST_APPLE)
  - include_directories (SYSTEM ${THIRDPARTY_LIB_ROOT}/protobuf/protobuf-2.5.0/include)
  - set(PROTOBUF_LIBRARIES ${THIRDPARTY_LIB_ROOT}/protobuf/protobuf-2.5.0/lib/libprotobuf.a)
  - set(PROTOBUF_PROTOC_EXECUTABLE ${THIRDPARTY_LIB_ROOT}/protobuf/protobuf-2.5.0/bin/protoc)
  + set(_mac_protobuf_version "2.5.0")
  + if (MAC_PROTOBUF_VERSION)
  + set(_mac_protobuf_version ${MAC_PROTOBUF_VERSION})
  + endif()
  + include_directories (SYSTEM ${THIRDPARTY_LIB_ROOT}/protobuf/protobuf-${_mac_protobuf_version}/include)
  + set(PROTOBUF_LIBRARIES ${THIRDPARTY_LIB_ROOT}/protobuf/protobuf-${_mac_protobuf_version}/lib/libprotobuf.a)
  + set(PROTOBUF_PROTOC_EXECUTABLE ${THIRDPARTY_LIB_ROOT}/protobuf/protobuf-${_mac_protobuf_version}/bin/protoc)
  set(PROTOBUF_FOUND On)
  else()
  