[clang] [clang-tools-extra] [libc] [libc][c11] implement ctime (PR #107285)

[Зишан Мирза via cfe-commits]

zimirza wrote:

Thank you for the thorough feedback. I apologize for going back and forth in this pull request. I will try to double check my work in future pull requests.

https://github.com/llvm/llvm-project/pull/107285