编译opencv 2.4.13error:1 /usr/include/string.h:652:42: error: ‘memcpy’ was not declared in this scope

在Ubuntu16.04下使用自带的gcc5.4版本没经过降级，安装opencv2.4.13的时候cmake成功，make的时候报错：

error:1 /usr/include/string.h:652:42: error: ‘memcpy’ was not declared in this scope

原因：g++版本太新了，需要兼容一下

解决办法：在上一级目录 CMakeLists.txt中前面添加

set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -D_FORCE_INLINES”)