`make install` does not remake whl package if only change .cc or .h (#10030)

`make install` does not remake whl package if only change .cc or .h

python/CMakeLists.txt

@@ -46,11 +46,11 @@ endif()
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/setup.py.in
     ${CMAKE_CURRENT_BINARY_DIR}/setup.py)
 
-
-add_custom_command(OUTPUT ${PADDLE_BINARY_DIR}/python/paddle/fluid/core.so
-        COMMAND cmake -E copy $<TARGET_FILE:paddle_pybind> ${PADDLE_BINARY_DIR}/python/paddle/fluid/core.so
+set(FLUID_CORE ${PADDLE_BINARY_DIR}/python/paddle/fluid/core.so)
+add_custom_command(OUTPUT ${FLUID_CORE}
+        COMMAND cmake -E copy $<TARGET_FILE:paddle_pybind> ${FLUID_CORE}
         DEPENDS paddle_pybind)
-add_custom_target(copy_paddle_pybind ALL DEPENDS ${PADDLE_BINARY_DIR}/python/paddle/fluid/core.so)
+add_custom_target(copy_paddle_pybind ALL DEPENDS ${FLUID_CORE})
 
 
 add_custom_command(OUTPUT ${PADDLE_PYTHON_BUILD_DIR}/.timestamp
@@ -61,7 +61,7 @@ add_custom_command(OUTPUT ${PADDLE_PYTHON_BUILD_DIR}/.timestamp
     COMMAND ${CMAKE_COMMAND} -E touch ${PADDLE_PYTHON_BUILD_DIR}/.timestamp
     COMMAND ${CMAKE_COMMAND} -E remove_directory ${PADDLE_PYTHON_BUILD_DIR}/lib-python
     COMMAND ${CMAKE_COMMAND} -E copy_directory ${PADDLE_PYTHON_BUILD_DIR}/lib* ${PADDLE_PYTHON_BUILD_DIR}/lib-python
-    DEPENDS gen_proto_py copy_paddle_pybind framework_py_proto profiler_py_proto ${PY_FILES} ${external_project_dependencies} ${COPY_PADDLE_MASTER})
+    DEPENDS gen_proto_py copy_paddle_pybind ${FLUID_CORE} framework_py_proto profiler_py_proto ${PY_FILES} ${external_project_dependencies} ${COPY_PADDLE_MASTER})
 
 set(paddle_python_deps ${PADDLE_PYTHON_BUILD_DIR}/.timestamp ${MKL_DEPENDS})
 if(NOT WITH_FLUID_ONLY)