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

[Зишан Мирза via cfe-commits]

zimirza wrote:

That is correct. Unfortunately, I did not compare my implementation with glibc's `ctime`. So, I created a new issue for this. Hope it is ok.

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