using find_package for swig (#334)

CMakeLists.txt

@@ -9,7 +9,7 @@ set(PADDLE_VERSION ${PADDLE_MAJOR_VERSION}.${PADDLE_MINOR_VERSION}.${PADDLE_PATC
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake")
 set(PROJ_ROOT ${CMAKE_SOURCE_DIR})
 include(package)
-include(swig)
+find_package(SWIG 2.0)
 find_package(CUDA QUIET)
 find_package(Protobuf REQUIRED)
 find_package(PythonLibs 2.7 REQUIRED)
@@ -60,6 +60,7 @@ include(flags)
 include(cudnn)
 include(FindPythonModule)
 include(check_packages)
+include(swig)
 include(coveralls)
 
 # add PaddlePaddle version

cmake/swig.cmake

-find_program(
-    SWIG_BINARY_PATH
-    swig)
-
-if(${SWIG_BINARY_PATH} STREQUAL "SWIG_BINARY_PATH-NOTFOUND")
-    set(SWIG_FOUND OFF)
-else()
-    set(SWIG_FOUND ON)
-endif()
-
-set(MIN_SWIG_VERSION 2)
-if(SWIG_FOUND)
-    execute_process(COMMAND sh -c "${SWIG_BINARY_PATH} -version | grep Version | cut -f3 -d' '"
-        OUTPUT_VARIABLE _SWIG_VERSION
-        OUTPUT_STRIP_TRAILING_WHITESPACE)
-    if(${_SWIG_VERSION} VERSION_LESS ${MIN_SWIG_VERSION})
-        message("swig version ${MIN_SWIG_VERSION} or greater is needed for generating python api. "
-                 "Only version ${_SWIG_VERSION} is found. Set SWIG_FOUND to FALSE")
-        set(SWIG_FOUND FALSE)
-    endif(${_SWIG_VERSION} VERSION_LESS ${MIN_SWIG_VERSION})
-endif(SWIG_FOUND)
-
 function(generate_python_api target_name)
     add_custom_command(OUTPUT ${PROJ_ROOT}/paddle/py_paddle/swig_paddle.py
                               ${PROJ_ROOT}/paddle/Paddle_wrap.cxx