主要用来解决，Eclipse中编译c++时，出现的std::threads,std::mutex等的unresolved问题

1、打开Project -> Properties -> C/C++ General -> Path and Symbols -> Tab [Symbols]. 添加 symbol : __cplusplus 并设定它的值为：201103L

2、project右键-> c/c++ build ->Settings -> GCC C++ Compiler -> Miscellaneous -> Other flags后面加上 -std=c++11

3、Window-> Preference -> Build -> Settings ->Discovery -> CDT GCC Built-in Compiler Settings MinGW(shared) ->(command to get compiler specs) ${COMMAND} -E -P -v -dD "${INPUTS}" -std=c++11