Add some posix thread sample code.

Signed-off-by: Yunchao Chen <ytu_cyc@126.com>
Merge branch 'master' of https://github.com/YunchaoChen/github

* 'master' of https://github.com/YunchaoChen/github:
  Add posix threads sample code.
Backup Sample code.

Signed-off-by: Yunchao Chen <ytu_cyc@126.com>