Merge pull request Tencent#1944 from ilelann/patch-1

Support CMake none targets

Author: miloyip

CMakeLists.txt

@@ -241,8 +241,10 @@ INSTALL(FILES "${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/${PROJECT_NAM
         DESTINATION ${CMAKECONFIG_INSTALL_DIR} )
 
 # Install files
-INSTALL(FILES
-    ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake
-    ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
-    DESTINATION "${CMAKE_INSTALL_DIR}"
-    COMPONENT dev)
+IF(CMAKE_INSTALL_DIR)
+  INSTALL(FILES
+      ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake
+      ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
+      DESTINATION "${CMAKE_INSTALL_DIR}"
+      COMPONENT dev)
+ENDIF()